JP3476334B2 - Semiconductor liquid phase epitaxial growth method and apparatus, and wafer holder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor liquid phase epitaxial growth method and apparatus for forming a semiconductor layer by performing epitaxial growth on a semiconductor wafer using a liquid source for epitaxial growth, and a wafer for storing and holding the wafer for epitaxial growth. Regarding wafer holder.

[0002]

2. Description of the Related Art In liquid phase epitaxial growth, a low melting point metal in a liquid state is used as a solvent, and a semiconductor material to be epitaxially grown is dissolved in the solvent to form a source. This is a technique for epitaxially growing a semiconductor on a wafer. GaP (gallium phosphide), GaAs (gallium arsenide), AlGaAs using Ga (gallium) as a solvent
Epitaxial growth of compound semiconductors such as (aluminum gallium arsenide), Ga (gallium) and Sn (tin)
It is used for the epitaxial growth of Si (silicon) using the as a solvent.

In principle, the liquid phase epitaxial growth method includes a step of bringing the source into contact with the wafer, a step of lowering the temperature of the source, and a step of separating the source from the wafer if necessary. Various liquid phase epitaxial growth apparatuses and methods such as a source injection method, a dipping method, and a slide boat method are known depending on the method of bringing a source into contact with or leaving a wafer.

In the source implantation method, a wafer is housed in, for example, a wafer holder and placed in an epitaxial growth chamber,
This is a method of performing epitaxial growth by injecting a source into the epitaxial growth chamber.

An example of a conventional device and method by the source injection method will be described with reference to FIG.

This epitaxial growth apparatus is usually called a boat and is used in a horizontal or vertical furnace. The boat shown in FIG. 14 is used in a horizontal furnace.
(A) shows a state of being placed in a furnace before starting epitaxial growth. However, the furnace and the core tube are omitted and not shown. The main part of the boat has a main body 5501, a source reservoir 5502, and a waste source reservoir 5503.
A partition plate 5504 is installed between the exhaust source reservoir 5503 and the exhaust source reservoir 5503. In addition, the wafer 550 is
An epitaxial growth chamber 5506 for accommodating 5 and performing epitaxial growth is provided. The source reservoir 5502 and the partition plate 5504 can be horizontally slid, and can be moved during the epitaxial growth process by a quartz rod (not shown) usually inserted from outside the furnace into the furnace.

When performing epitaxial growth, the process shown in FIG.
The wafer 5505 is placed in the epitaxial growth chamber 5506 as shown in FIG. Wafer 5505 is shown in FIG.
It is held vertically as shown in FIG. 4, or horizontally or diagonally. Further, FIG. 14 does not show a wafer holding mechanism such as a wafer holder. The source reservoir 5502 stores the raw material of the epitaxial source. The raw material for the epitaxial source is, for example, Ga.
In the case of As epitaxial growth, the metal Ga used as a solvent
And epitaxial growth materials such as poly-GaAs and Si
And other dopants are added.

In this state, the boat is introduced into the furnace and the temperature is raised to wait until the source material is melted in the Ga metal and the source 5507 saturated with the epitaxial growth material is obtained. In general, it takes a long time of 1 hour or more to obtain the source 5507. When the source 5507 is obtained, FIG.
Slide the sauce reservoir 5502 to the left as in (b),
The hole 5081 provided in the source reservoir 5502 is formed in the source passage 55.
Set to 09. By this operation, the source 5507 flows into the epitaxial chamber 5506 through the source passage 5509 and comes into contact with the wafer 5505. Wafer 5
By lowering the temperature in a state where 505 and the source 5507 are in contact with each other, the epitaxial growth raw material in the oversaturated source 5507 is deposited on the wafer and epitaxially grows.

When the desired amount of epitaxial growth is obtained, the partition plate 5504 is slid to the left as shown in FIG. 14 (c) to form a hole 5085 in the partition plate 5504.
Outlet 508 provided in the epitaxial growth chamber 5506
Set to 3. By this operation, the used epitaxial source 5507 falls into the exhaust source reservoir 5503, and the epitaxial growth is completed.

Although the apparatus and method for performing epitaxial growth of only one layer have been described with reference to FIG. 14, generally, in the source injection method, after discharging the source used for epitaxial growth, a new source is injected to form a multi-layer structure. Epitaxial growth can be performed.

FIG. 15 shows, by way of example, an apparatus for performing epitaxial growth of two layers. The source reservoir 6602 is divided into left and right, and independent inlets 6081 and 608 are provided.
2 and accommodates a first source 6071 and a second source 6072, respectively. The source reservoir 6602 is slid to the right, the left first source 6071 is injected to perform the first epitaxial growth, and after the first epitaxial growth is completed, the first source is discharged, and then the source reservoir is 6602 slide to the left and the second source 6 on the right
By injecting 072, two layers of epitaxial growth can be continuously performed.

The dipping method is a method in which a source reservoir containing a source material is placed in a heating furnace, and the source material is melted by heating to be an epitaxial growth source, and a wafer is dipped therein. After that, the temperature of the heating furnace is lowered to perform epitaxial growth to perform epitaxial growth with a predetermined film thickness, and then the wafer is pulled up from the source to complete the epitaxial growth.

The slide boat method is a method in which a wafer is held on a wafer holder, a slider containing a source is placed on the wafer holder, and when the temperature reaches a predetermined temperature, the slider is moved to bring the source into contact with the wafer for epitaxial growth. is there.

However, the conventional liquid phase epitaxial growth method has some problems in principle, and will be listed below in connection with the epitaxial growth method and the wafer holder for holding the wafer. (1) Polycrystalline precipitation and non-uniform film thickness liquid phase epitaxial growth is a method in which a supersaturated solute is deposited and grown on the wafer. The solute diffuses and moves in the source due to the concentration gradient generated by the precipitation. To reach. The solute cannot reach the wafer from the source located at a position away from the wafer, and is deposited as polycrystal in the source or on the wall surface of the boat.

Since the polycrystal grows non-uniformly, if it is deposited in the source near the epitaxial growth surface of the wafer or on the opposite surface or the periphery of the wafer, the epitaxial growth is hindered by the deposition of the poly crystal, and the non-uniformity of the epitaxial growth thickness is cause.

In the injection method, a source passage for guiding the source from the source reservoir to the epitaxial growth chamber is indispensable. However, polycrystalline deposits and adheres to the source passage to prevent inflow and outflow of the source. Such a phenomenon is particularly fatal when the source is exchanged and the second layer is grown after the first semiconductor layer is grown.

In the dipping method, the precipitation of polycrystals on the outer edge and the peripheral portion of the wafer becomes a problem. When the wafer is simply put into the source for epitaxial growth, the solute of the source is naturally deposited on the back surface of the wafer and epitaxially grows. In order to prevent this, for example, Japanese Patent Laid-Open No. Hei 4
As shown in FIG. 16 of Japanese Unexamined Patent Publication No. 160092, a wafer 14 is placed in a shallow petri dish 13 and a large number of the dishes are stacked and fixed by a cassette 15, which is placed in a source 12 for epitaxial growth. The method of making it proposed is proposed.

In this method, since the back surface of the wafer is in close contact with the dish, it does not come into contact with the source, so that epitaxial growth on the back surface does not occur. Also, if a large number of plates are used, it is possible to perform epitaxial growth on a large number of wafers at once.

On the other hand, since the wafer is held horizontally in the dish for the epitaxial growth, the source remains on the upper surface of the wafer even if the wafer and the wafer holder are pulled out from the source after the predetermined epitaxial growth is completed, and the epitaxial growth is promptly performed. I can't finish it. As a result, it becomes difficult to control the film thickness of the semiconductor layer, and non-uniformity of the residual source occurs, resulting in uneven thickness between wafers and within the wafer surface, and reduction in flatness of the epitaxial growth surface.

Further, there arises a problem that the polycrystal is deposited on the bottom of the dish, which is the opposite surface of the wafer, and the film thickness of the epitaxial growth layer becomes uneven.

On the other hand, as shown in FIG. 17 of Japanese Unexamined Patent Publication No. Sho 60-21897, a dipping method has been proposed in which the back surface of the wafer is brought into close contact with the spacer.

However, this method does not consider diffusion of solute from the periphery of the wafer and deposition on the edge of the wafer. FIG. 18 shows a state in which the wafer 1905 is dipped in the source 1907 and epitaxial growth is performed. Since the back surface of the wafer 1905 is in close contact with the spacer 1911, growth does not occur. However, as described above, in the liquid phase epitaxial growth, the solute in the source on the wafer surface is diffused and deposited on the wafer surface to cause epitaxial growth. As schematically shown in FIG. 18, in the central portion of the wafer 1905, only the source between the opposed wafers contributes to the growth. On the other hand, at the edge of the wafer 1905, the source around the wafer also contributes to the growth. As a result, the wafer 19
The edge portion of 05 is epitaxially grown thicker than the central portion, and the in-plane uniformity of the thickness of the epitaxial growth layer is deteriorated.

Further, generally, since the edge portion of the wafer is chamfered, the orientation of the crystal differs from that of the surface, and since it is not flat, abnormal growth such as polycrystal growth easily occurs.

Further, in the dipping method, a solute is deposited in the source in the source reservoir, and the solute is lighter than Ga of the solvent and floats up. The solute deposited in the source under the wafer holder during epitaxial growth, eg, polycrystalline GaAs, adheres to the wafer holder and the wafer in the source. Further, the solute floating on the surface of the epitaxial growth source adheres to the upper part of the wafer when the wafer is pulled up after the epitaxial growth is completed.

As described above, the technique proposed in Japanese Patent Application Laid-Open No. 60-21897 does not consider measures against abnormal growth in the peripheral portion of the wafer, uneven epitaxial growth thickness, and solute precipitated in the source. (2) Heat Degradation of Wafer Since GaAs has a high vapor pressure of As, As is evaporated from the surface when exposed to high temperatures, the surface deteriorates. In order to prevent the evaporation of As, it is necessary to avoid placing the wafer at a high temperature for a long time, and to increase the As vapor pressure around the wafer to prevent the evaporation, and place the wafer in a tightly sealed and narrow space as much as possible. For example, when heat-treating a GaAs wafer, a silicon oxide film is formed on the surface of the wafer and As
A method such as so-called cap anneal for preventing the evaporation of the is adopted.

However, in the liquid phase epitaxial growth, the melting of the source material requires a high temperature above the epitaxial growth temperature and a long time, so the wafer is exposed to the high temperature even during the preparation stage until the epitaxial growth becomes possible. In addition, since the epitaxial surface of the wafer needs to be in contact with the source, the wafer surface cannot be completely covered.

In the implantation method, since the wafer is held in the boat below the source and put into the high temperature part in the furnace together with the source material, the wafer is exposed to high temperature for a long time. Further, since the source injection passage communicates with the epitaxial growth chamber where the wafer is placed, the wafer cannot be sealed in a narrow space.

In the dipping method, the wafer can be placed outside the heating furnace or at a low temperature inside the furnace until the epitaxial growth is ready. However, preheating is required to bring the wafer to the same temperature as the source immediately before dipping, and thermal deterioration during this period is inevitable.

The method of placing the wafer in the low temperature section is described in G
The growth of aP is disclosed in JP-A-60-115271. In this method, during preheating, the wafer is placed above the liquid surface of the source in the source reservoir, and the source reservoir is covered to seal the wafer.

However, the reason why the source reservoir is covered is to prevent oxygen vaporization of the dopant source from the epitaxial growth source, and since the space in the source reservoir is large, it was not sufficient to prevent thermal deterioration of the wafer.

Further, in this method in which the wafer is placed in a low temperature part other than the furnace, the temperature gradient in the reaction tube in which the substrate is placed drops sharply from the part where the reaction tube goes out of the furnace. When the substrate is placed outside the furnace, there is a problem that a large temperature distribution is generated in the surface of the substrate and stress is generated. Also,
There is a problem that thermal stress occurs due to a large temperature difference when the wafer is lowered to a high temperature portion in the furnace. When the stress is generated, the substrate warps and crystal defects are caused. (3) Inhomogeneous composition of epitaxial growth source For example, in liquid phase epitaxial growth of GaAs, metal Ga serving as a solvent and polyGaA as an epitaxial growth material are used.
Then, s, and a dopant such as Si are put in the source reservoir, the temperature is raised, and they are melted to form an epitaxial growth source. However, it is difficult to obtain a uniform solution only by spontaneous diffusion.
As, which is lighter than a, has a high concentration near the surface of the source and tends to be unsaturated at the bottom of the source reservoir. Also, the epitaxial growth raw material added in a small amount like a dopant is
There is a problem that it tends to be non-uniform in the source. This is because the epitaxial growth raw material is provided as a solid and cannot be uniformly arranged in the source reservoir.

As a countermeasure against this, stirring the sauce in the sauce reservoir can be considered. However, since the boat used in the horizontal furnace described above needs to be driven to stir in the lateral direction, it was difficult to install the stirrer and the mechanism.

In the dipping method using the vertical furnace, it is relatively easy to install the stirring mechanism, but in the dipping method, the source saturation at the time of wafer dipping becomes a problem. If the source is unsaturated, the problem of the wafer melting at the same time it comes into contact with the source occurs regardless of the epitaxial growth method. If the source is supersaturated, the deposited solute covers the source surface. Therefore, particularly in the dipping method, there is a constraint that the source should not be oversaturated. (4) When the epitaxial growth of two or more layers is continuously performed by the method in which the epitaxial growth raw material remains and is mixed, the second source is injected after discharging the first source. However, polycrystals are also deposited and attached from the first source. Particularly, in the source injection method, such a phenomenon is more remarkable because there is a large space such as a source passage where an originally unnecessary source for epitaxial growth can enter. This deposit is not discharged even when the source is discharged, and remains in the boat body together with the sauce entangled with the deposit. Here, when the second source is injected, the first source component is mixed into the second source.

For example, when AlGaAs is epitaxially grown subsequently to GaAs epitaxial growth, since the GaAs source is mixed with the AlGaAs source, the Al mixed crystal ratio of the AlGaAs layer is reduced or nonuniform, and the dopant concentration cannot be controlled. There is a problem that becomes.

In the dipping method, a plurality of source reservoirs and sources are prepared, and wafers are sequentially inserted to carry out epitaxial growth. As shown in FIG. 17 of Japanese Patent Laid-Open No. 4-160092 mentioned above, since the wafer is housed in the dish-shaped wafer holder, it is difficult to discharge the sources, and the sources left on the wafer are mixed with each other, and the source composition is likely to change. However, it is difficult to obtain an epitaxial growth layer having a desired thickness and composition.

In view of the above-mentioned circumstances, the present invention takes into consideration the problems such as polycrystal precipitation, film thickness non-uniformity, thermal deterioration of wafer, non-uniform composition of epitaxial growth source, residual and mixing of epitaxial growth raw materials, which have occurred in the prior art. It is an object of the present invention to propose a semiconductor liquid phase epitaxial growth method capable of solving various problems, an apparatus therefor, and a wafer holder used for performing epitaxial growth.

[0037]

The wafer holder of the present invention has a wafer storage space for holding the back surfaces of at least one set of semiconductor wafers in contact with the inner side walls so that the front surfaces face each other with a predetermined gap therebetween. A pouring outlet for pouring and ejecting a source into the wafer storage space, or a holder main body provided with an inlet for injecting a source into the wafer storage space and a discharge outlet for discharging the source from the wafer storage space, And a holder cover for covering the opening surface of the holder body.

The epitaxial growth apparatus of the present invention is a source holder that stores a source used for liquid phase epitaxial growth, and a wafer holder that holds a semiconductor wafer. Having a wafer storage space that holds the wafers facing each other at a predetermined interval, a pouring outlet for pouring and ejecting a source into the wafer storage space, or an inlet for pouring a source into the wafer storage space and the wafer storage A holder main body provided with a discharge port for discharging the source from the inside, a wafer holder having a holder cover covering the opening surface of the holder main body, and located below the source reservoir,
An epitaxial growth chamber for storing a semiconductor wafer held by the wafer holder, a source passage provided between the source reservoir and the epitaxial growth chamber, and a front chamber provided in a part of the source passage,
The source is agitated in the front chamber when the source stored in the source reservoir passes through the source passage and is introduced into the epitaxial growth chamber.

Another epitaxial growth apparatus of the present invention is
A heating furnace having a high temperature soaking region which is heated by a heating means to form a substantially uniform temperature distribution, and a low temperature region which is located above the high temperature soaking region and which is lower in temperature than the high temperature soaking region, A gas supply means for supplying a reducing gas and / or an inert gas to the heating furnace, and a solute containing a semiconductor material used for epitaxial growth, which is installed in the high temperature soaking region in the heating furnace, is dissolved in a solvent containing a metal. The source reservoir for containing the source, a wafer holder for holding a plurality of semiconductor wafers, and the wafer holder is moved vertically in the heating furnace, when performing epitaxial growth, the semiconductor wafer held by the wafer holder Wafer holder moving means for immersing the source in the source reservoir, a stirring blade for stirring the source in the source reservoir, and the stirring blade It is moved in the vertical direction, characterized in that it comprises a stirring blade moving means for loading and unloading the stirring blade in the source.

The semiconductor liquid phase epitaxial growth method of the present invention is a step of holding a plurality of semiconductor wafers in a wafer holder, wherein the back surfaces of at least one set of semiconductor wafers are brought into contact with the inner sidewalls and the surfaces are opposed to each other with a predetermined gap. A holding hole for holding the wafer so that the source is poured into and discharged from the wafer storing space, or an inlet for injecting the source into the wafer storing space and a discharge for discharging the source from the wafer storing space. Using a wafer holder having a holder main body provided with an outlet and a holder cover for covering the opening surface of the holder main body, a step of holding a semiconductor wafer, and storing the semiconductor wafer held by the wafer holder in an epitaxial growth chamber. And a reducing gas and / or an inert gas in the epitaxial growth chamber. And a step of heating the epitaxial growth chamber to a predetermined temperature,
After the source contained in the source reservoir flows into the front chamber and is stirred, a step of introducing the source into the epitaxial growth chamber to bring the source into contact with the semiconductor wafer, and lowering the temperature in the epitaxial growth chamber, The method is characterized by including a step of performing epitaxial growth on the wafer and a step of discharging the source in the epitaxial growth chamber and ending the epitaxial growth.

The semiconductor liquid phase epitaxial growth method of the present invention is a step of holding a plurality of semiconductor wafers in a wafer holder, and the inner back surfaces of at least one set of semiconductor wafers are brought into contact with the side walls and the surfaces are opposed to each other with a predetermined gap. Has a wafer storage space for holding, and a source / outlet for injecting / discharging a source into / from the wafer storage space, or an inlet for injecting a source into the wafer storage space and a source for discharging from the wafer storage space. A step of holding a semiconductor wafer by using a wafer holder having a holder main body having a discharge port for allowing the holder main body to cover an opening surface of the holder main body, and heating by a heating means to form a substantially uniform temperature distribution. And a low temperature region located above the high temperature soaking region and at a temperature lower than the high temperature soaking region. A step of holding the wafer holder holding a semiconductor wafer in the low temperature region of the heating furnace having an area, a step of flowing a reducing gas and / or an inert gas into the heating furnace, and the heating furnace Heating the inside of the high temperature soaking region to a predetermined temperature by the heating means, lowering the wafer holder from the low temperature region to the position of the high temperature soaking region, and setting the wafer holder and the semiconductor wafer to the predetermined temperature. A step of raising the temperature to a temperature and a step of moving the wafer holder and the semiconductor wafer downward, and putting the solute containing a semiconductor material used for epitaxial growth in the source in a source reservoir containing a source in which a solvent containing a metal is dissolved A step of lowering the temperature of the high temperature soaking region to perform epitaxial growth on a semiconductor wafer, Pull the da from said source, characterized in that it comprises a step of terminating the epitaxial growth.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. (1) Wafer Holder According to the First Embodiment FIG. 1 shows the structure of the wafer holder according to the present embodiment. FIG. 1A shows the structure of the side surface of the wafer holder B.
1B is a vertical sectional view taken along the line -B, FIG. 1B is a vertical sectional view taken along the line AA showing the structure of the front surface, and FIG.

As shown in FIG. 1 (a), this wafer holder holds a plurality of wafers 15 vertically or diagonally with the front and back alternately, and the backsides of the wafers are separated by the wafer holder 14. It has a structure that holds the surfaces facing each other with a space between them. Further, as shown in FIG. 1B, the wafer 15 is put in the U-shaped pocket of the wafer holder body 11 and fixed by the cover 12 inserted in the pocket. The shapes of the U-shaped pocket and the cover 12 match the outer peripheral shape of the wafer, and the periphery of the wafer 15 is covered with the pocket and the cover 12. The cover 12 is inserted laterally when viewed as being put in the furnace. Further, as shown in FIGS. 1B and 1C, this wafer holder has a pouring port 13 for pouring and discharging an epitaxial growth source between the surfaces of the wafer 15 at the bottom thereof. . The upper slit 16 corresponds to a gas vent when the source is injected and discharged.

When the wafer holder according to the present embodiment is used for the dipping method, it is used when the wafer holder is pulled out from the source to end the epitaxial growth, and in the implantation method, the source is discharged from the epitaxial chamber to end the epitaxial growth. Is assumed. Therefore, the wafer is held vertically or diagonally so that the source quickly flows off the wafer.
Further, the discharge port is provided at the lowermost part between the wafers.

The structure of holding two wafers 15 back to back via the wafer holder 14 is also one of the features of this embodiment. By bringing the back surface of the wafer 15 into close contact with the wafer holder 14, it is possible to prevent epitaxial growth on the back surface of the wafer, which tends to be a problem in the dipping method. Further, by holding a plurality of wafers 15 in the wafer holder 14, the number of wafers that can be accommodated in the wafer holder is increased, and as a result, the number of wafers that can be epitaxially increased at one time and productivity can be improved.

The structure in which the surfaces for epitaxial growth are held so as to face each other at a constant interval is also one of the characteristics of this wafer holder. By making the epitaxial growth surfaces face each other, polycrystalline precipitation on the facing surface does not occur,
An epitaxial growth layer having a uniform thickness and a flat surface can be obtained.

The fact that the present wafer holder can easily prevent the precipitation of polycrystals and discharge the source is particularly effective when the epitaxial growth is performed for two or more layers by using the implantation method or the dipping method.

The distance between the epitaxial growth surface and the facing surface of the wafer, that is, the thickness of the source on the wafer is an important factor for controlling the thickness of the epitaxial growth layer.
Since the solute in the source on the wafer surface diffuses to the wafer surface and precipitates to form an epitaxial growth layer, the thickness of the epitaxial growth layer is in principle proportional to the thickness of the source. It is efficient to reduce the thickness of the source to the minimum necessary so that the source is not wasted. However, if the distance between the wafer and the facing surface is less than a certain value, the source does not flow onto the wafer even if the wafer is placed in the source, or the source does not flow down even if the wafer is pulled up from the source, and epitaxial growth starts. And lose control of the end. If the epitaxial growth surfaces of the wafer are opposed to each other, the minimum required source thickness will be doubled, and the inflow and outflow of the source can be facilitated.

The specific wafer interval may be 0.3 mm or more, but it is more preferably 0.5 mm or more. Below 0.2 mm, the source may not get between the wafers. When the thickness is 0.4 mm or less, when the wafer is pulled out from the source, the source may remain between the wafers due to the surface tension of the source.

On the other hand, if the distance between the wafers is too wide, the solute in the source that has entered between the wafers cannot reach the wafer during the epitaxial growth and is deposited in the source. In order to prevent such precipitation, the wafer interval is preferably 5 mm or less.

Since the diffusion of the solute depends on the time for which it is kept supersaturated, that is, the reciprocal of the cooling rate, the wafer interval at which precipitation occurs also depends on the cooling rate. The following equation (1) is
It is obtained by an experiment, and it is desirable to set the wafer interval within the range of this equation (1).

Wafer spacing (mm) ≦ 3.1 × (1 / temperature-falling rate (° C./min)) ^1/2 (1) The wafer 15 has a stepped portion 1 provided in the holder body 11.
It is stored in 7. A similar step is also provided on the cover 12. The wafer 15 is accommodated on the side where the diameter of the step is large, and the diameter of this portion is made larger than the diameter of the wafer in consideration of thermal expansion of the wafer. Since the side of the step portion 17 opposite to the back surface of the wafer 15 covers the edge of the wafer 15, the diameter of this portion is preferably smaller than the diameter of the wafer 15. This is to prevent the wafer from being separated from the predetermined position even if buoyancy is applied to the wafer in the source or the boat accommodating the wafer holder is moved.

However, if the diameter of this portion is made too small, the area of the portion where epitaxial growth is possible on the wafer surface becomes small, so it is desirable that the diameter of the cover portion be as large as possible.

Generally, since the periphery of the wafer is chamfered, the orientation of the crystal is different from that of the surface on which the epitaxial growth is performed, and abnormalities such as the growth of polycrystalline semiconductor are likely to occur in the peripheral portion. Therefore, the peripheral portion is mechanically removed after the epitaxial growth is completed, or the semiconductor element formed on the peripheral portion is removed, and the peripheral portion of the wafer is not substantially used. Although this unusable region varies depending on the conditions such as the type and thickness of the epitaxial growth layer, the bevel portion is 1 mm or less from the outermost periphery, so it is common to remove 2 mm from the outermost periphery of the wafer for safety. Therefore, by limiting the portion where the wafer holder contacts the wafer within 2 mm from the outermost periphery of the wafer, the loss of abnormal growth due to the contact of the wafer with the wafer holder can be substantially eliminated. That is, the diameter of the step portion 17 on the front surface side of the wafer is preferably equal to or larger than a value obtained by subtracting 4 mm from the diameter of the wafer.

Alternatively, if the epitaxial growth is performed without bringing the source into contact with the chamfered portion of the wafer edge, the edge does not grow abnormally. Therefore, the step portion 1
It is desirable that 7 covers the chamfered portion of the edge.

In the dimension design of the wafer holder including the diameter, it is necessary to consider the difference in thermal expansion between the wafer holder and the wafer.

The wafer holder according to the present embodiment is also characterized in that it covers the periphery of the wafer to prevent the source from entering the periphery or side surface of the wafer, or limits the source to a small amount.

The smaller the gap around the wafer, that is, the distance from the wafer edge to the wafer holder or the cover, the more uniform the epitaxial growth film thickness. Conversely, if the gap is large and the solute that is the epitaxial growth material becomes larger than the distance that can diffuse in the source,
The epitaxial growth film thickness tends to be non-uniform. As described above, the diffusion distance depends on the temperature lowering rate during epitaxial growth. The distance obtained by the experiment is half of the equation (1) when there are wafers on both sides, and the cooling rate is 0.1 ° C /
4.9 mm for min, 2.5 m for 0.4 ° C / min
In the case of m and 1 ° C./min, it becomes 1.6 mm. Therefore, it is desirable that the distance between the wafer edge and the wafer holder be 4.9 mm or less.

Similarly to the distance between the opposing wafers, if the gap between the wafer edge and the wafer holder is less than 0.5 mm, it becomes difficult for the source to enter the edge of the wafer. In order to absorb the difference in thermal expansion between the wafer and the wafer holder, it is desirable that the wafer holder has a margin of less than 0.5 mm.

A characteristic of the wafer holder according to the present embodiment is that, when the wafer holder is viewed in the furnace, the pocket inlet / outlet is provided in the lateral direction of the holder and the wafer and the cover are inserted from the side. is there. A vertical force of buoyancy in the epitaxial growth source, which has a large own weight and a large specific gravity, is applied to the wafer stored in the wafer holder. Therefore, by vertically inserting the wafer and the cover, the vertical movement can be surely restricted by the holder body. (2) Wafer Holder According to Second Embodiment FIG. 2 shows the structure of the wafer holder according to the second embodiment of the present invention. 2A is a vertical sectional view taken along the line BB showing the side structure of the wafer holder, FIG. 2B is a vertical sectional view taken along the line AA showing the front structure, and FIG. It is a bottom view.

The structure, name, number, and action of each part in this embodiment are basically the same as those in the second embodiment shown in FIG. 1, but different in the following points.

In the present embodiment, the wafer 15 is housed in the tapered portion 18 instead of the stepped portion in the space of the holder body 11a. When the step portion is provided, a wafer holder must be prepared for each thickness of the wafer, but the taper portion 18 can be stored even when the thickness of the wafer is different. Further, before the epitaxial growth is started, the wafer 15 is pressed against the lower taper by its own weight, and is pressed against the upper taper by buoyancy during the epitaxial growth, so that the wafer 15 adheres to the wafer holder 14a.
By manufacturing the wafer holder 14a with a material having good thermal conductivity such as carbon, the in-plane temperature distribution of the wafer 15 in close contact with the wafer holder 14a becomes constant, and uniform epitaxial growth can be performed.

For the same reason as in the first embodiment, the minimum diameter of the taper portion 18 is preferably smaller than the diameter of the wafer and equal to or larger than the value obtained by subtracting 4 mm from the diameter of the wafer, and the wafer is not chamfered. It is desirable that the diameter is equal to or larger than the diameter of the portion.

In the present embodiment, no gas vent is provided. However, the gas is the holder body 11a and the cover 1
Since it can go in and out through a gap such as between 2a, the source can be taken in and out by controlling the injection and discharge rates of the source.

The source inlet / outlet port 13a of the present embodiment does not open to the back surface of the wafer 15 as in the first embodiment, and the wafer 15 as shown in FIG.
Of the wafer holder 14a, which is open to the middle of the cross section of the wafer holder, and forms a step with the wafer holder 14a to which the back surface of the wafer adheres.

FIG. 3 shows the positional relationship in section between the wafer holder 14a, the wafer 15, and the pouring / discharging port 13a. Figure 3
(A) shows the wafer holder 1 as in the first embodiment.
4A and the pouring outlet 13a are set to the same height. In this case, since the injected source hits the side surface of the wafer 15, the source may go around to the back surface. Further, it is important to limit the amount of the source that enters the side surface of the wafer 15 or not to put the source, but in the structure shown in FIG. The sauce enters the pouring outlet 13a
The solute diffuses from the source. Therefore, the wafer 15
The thickness of the epitaxially grown film increases near the pouring / exhausting port 13a at the edge.

FIG. 3B shows a structure in which the level difference of the pouring / discharging port 13a is set higher than the wafer holder 14a by the thickness of the wafer. In this case, the wafer 15 is stored in the step between the two. Since the source is injected into the front surface of the wafer, it does not go around to the back surface, and nonuniformity of the epitaxial growth film thickness in the vicinity of the edge of the wafer 15 that hits the pouring port 13a does not occur.

FIG. 3C shows a case where the pouring / discharging port 13a is higher than the wafer holder 14a by half the thickness of the wafer 15. This step has a height of half the wafer thickness, but the edge of the wafer 15 is rounded so that the source does not go around to the back surface. The effect of making the epitaxial growth film thickness uniform is inferior to that of the structure shown in FIG. 3 (b), but the wider the thickness of the pouring / discharging port 13a, the easier source / removal of the source.

As described above, it is indispensable to provide the step so that the source does not come into contact with the pouring / exhausting portion on the side surface of the wafer 15 when the wafer holder 14a is omitted and the back surfaces of the wafers are directly adhered to each other. Becomes This is because if epitaxial growth is performed by bringing the source into contact with the side surface of the wafer while keeping the back surface of the wafer in close contact, the two wafers may be united due to the growth on the side surface of the wafer. (3) Wafer Holder According to Third Embodiment FIGS. 4 and 5 show a wafer holder according to a third embodiment of the present invention. FIG. 4 shows a structure in which ten holder plates each including the holder plate 11b and the insertion-type cover 12b are combined. Pressing plates 19 are provided on both sides of the holder plate. FIG. 5 shows a sectional structure of each holder plate 11b and the cover 12b, and a procedure for housing the wafer 15.

The wafer holder 11b has a holder body 14
Tapered portion 1 for accommodating two wafers 15 on one side of b
8b. The minimum diameter of the tapered portion 18b is set to 75.2 mm, the maximum diameter is set to 77.0 mm, and the taper angle is set to 45 degrees with respect to the wafer diameter of 76.0 mm.
When a wafer 15 having a thickness of 0.35 mm is used, the distance between the facing wafers is set to be 2 mm. The material of the holder body 14b is high-purity carbon.

As shown in FIG. 5 (a), the wafer 15 is inserted into the taper portion 18b of the U-shaped groove portion of the holder plate 11b placed horizontally in a direction in which the surface is exposed from the lateral direction. As shown in FIG. 5B, the cover 12b is inserted and the wafer 15 is fixed. The cover 12b is also provided with a similar tapered portion 18b. As shown in FIGS. 5C and 5D, the second wafer 15 is inserted into the taper portion 18b from the upper side to the lower side. Next, as shown in FIG. 5 (e), after the next holder plate 11 is overlapped with another holder plate in the same manner,
Finally, the pressing plate 19 is overlaid. When the whole is put up, the two wafers 15 and 15 are stored with their front surfaces facing each other and their back surfaces back to back in the wafer holder 14b.

The fixing of the stacked wafer holders 14b is not shown in FIG.
A through hole may be provided in a portion other than the groove portion of 4b to allow a pin or a screw to pass through. Alternatively, a case having a size for accommodating a plurality of wafer holders may be prepared, and the holder plate may be placed in the case.

When the wafers are put in after the holder plates are first stacked, the wafer is rotated at the time of storage because the groove is deep and the groove is thin, and the orientation flat of the wafer, that is, the orientation of the crystal orientation is constant. Difficult to do. In this embodiment, since the wafers are stored while the holder plates are laid down and stacked, the orientation of the wafers can be easily adjusted. (4) Wafer Holder According to Fourth Embodiment FIG. 6 shows a wafer holder according to a fourth embodiment of the present invention. The entire structure is shown in FIG. 6 (a), and FIG.
The vertical sectional structure taken along line CC is shown in FIG.

The holder plate 11c according to the present embodiment has a semi-circular groove portion consisting of a tapered portion 18c in the peripheral region except the opening surface side of the central circular holder holding plate 14c.
The cover 12c is also provided with a groove having a similar taper 18c. The cover 12c is in a state in which the holder holding plate 14c of the holder plate 11c fits into a groove existing between the tapers 18c and is fixed. The inlet / outlet port 13c and the gas vent groove 16c provided on the holder plate 11c are stepped with respect to the holder holding plate 14c by the thickness of the wafer 15 as shown in FIG. 3B.

The holder holding plate 14c has a circular shape so that the orientation of the wafer 15 can be easily adjusted when the wafer 15 is stored in the holder plate 11c.

The wafer holder according to the present embodiment has two
The wafer 15 is stored in the holder plate 11c, and the cover 1
2c can be attached, and one set in that state can be laminated or aligned in a case to be integrated. Alternatively, only a plurality of holder plates 11c may be laminated and fixed, the wafer 15 may be housed in the holder plates 11c, and the cover 12c may be attached. In this case, the cover has a one-to-one correspondence with the holder plate.
However, it is also possible to adopt a structure in which a cover for covering a plurality of holder plates is integrated. (5) Epitaxial growth method and apparatus therefor according to the fifth embodiment. Next, it is more effective to use the wafer holders according to the above first to fourth embodiments, which is a source injection type liquid used in a horizontal furnace. A boat for phase epitaxial growth, a liquid phase epitaxial growth method using the same, a dipping type apparatus using a vertical furnace, and the method will be described. However, the following embodiments are not limited to the above-mentioned wafer holder, and other types of wafer holders may be used.

FIG. 7 shows an epitaxial growth method according to the fifth embodiment step by step. In this embodiment, the boat described above is used to perform epitaxial growth of two layers of GaAs and AlGaAs on a GaAs wafer.

FIG. 7A shows a state in which the wafer 10105 is placed in the furnace before starting the epitaxial growth. Here, the furnace and the core tube are omitted and not shown.

The main part of the boat has a main body 10101, a source reservoir 10102, and a waste source reservoir 10103.
Partition plate 101 is provided between 101 and exhaust source reservoir 10103.
04 is installed. In addition, the wafer 10
An epitaxial chamber 10106 which accommodates 105 and performs epitaxial growth is provided. A front chamber 10110 is provided in the main body 10101, and the front chamber 10110 is connected to the epitaxial growth chamber 10106 by a source passage 10109. In the source passage 10109, the control rod 101
11 has been inserted.

Source reservoir 10102, control rod 1011
1. The partition plate 10104 can be horizontally slid, and can be moved during the epitaxial process by a quartz rod (not shown) inserted from outside the furnace into the furnace.

Before starting the epitaxial growth, as shown in FIG.
As in (a), the wafer 10105 is held in the epitaxial growth chamber 10106. The method of holding the wafer and the wafer holder are not particularly limited in the present embodiment, but as shown in FIG. 7, the epitaxial growth surfaces of the two wafers are vertically opposed to each other with a space therebetween. Good. Further, it is desirable that the entire circumference of the wafer is covered with a wafer holder to ensure only a space for containing the minimum source required for epitaxial growth.

The source material for the epitaxial growth source is placed in the source reservoir 10102. In this embodiment, the source reservoir 10102 is divided into left and right sides. A first source 11071 for epitaxially growing GaAs is placed on the left side of the figure, and a second source 11072 for epitaxially growing AlGaAs is placed on the right side. ing. First
The source material may be in a weight ratio of, for example, 100 for metal Ga, 15 for poly GaAs, and 0.3 for dopant Si. The second source material is metal Ga 100 and poly G
aAs is 5.6, metallic Al is 0.1, and Zn is a dopant.
May be 0.06.

In this state, the boat is placed in the furnace and heated to 950 degrees Celsius in a hydrogen atmosphere to melt the source material. After about 1 hour, the temperature is lowered to 920 degrees Celsius and the source injection is started to start the epitaxial growth.

First, as shown in FIG. 7B, the source reservoir 101
02 is slid rightward to introduce the first source 11071 into the anterior chamber 10110.

If there is no front chamber as in the conventional apparatus, the source flows directly from the source reservoir into the epitaxial chamber. Therefore, if the source composition is not uniform in the source reservoir, the sources injected into the epitaxial growth chamber will be non-uniform, for example, the source composition will be different at the beginning and end of the implantation. In this embodiment, since the antechamber 10110 is provided, the sauces are mixed when flowing into the antechamber 10110, and the whole is made uniform. In addition, in the front chamber 10110, Ga
By keeping a mass of As, even if the source is not saturated due to insufficient dissolution in the source reservoir, the front chamber 10110
Becomes saturated inside.

Next, as shown in FIG. 7C, the control rod 1011
1 is slid to the right and is injected into the epitaxial growth chamber 10106 through the source through the source passage 10109.
Contact the wafer 10105.

Next, as shown in FIG. 7D, the control rod 1011 is
1 is the source passage 10109 on the left side and the partition plate 10104.
Return it to a position where it will not block. In this state, the epitaxial growth chamber 10106 is cut off from the source passage 10109.

Next, as shown in FIG. 7E, the partition plate 10
104, slide to the right, and the source outlet 11083
And 11084 are combined, and the source remaining in the antechamber 10110 and / or the source passage 10109 is drained.
Discharge to the chamber on the left side of 03.

In the state of FIG. 7 (e), the temperature of the furnace is lowered and Ga
As epitaxial growth is performed. For example, the cooling rate can be 0.8 degrees Celsius / minute.

During the epitaxial growth, the epitaxial growth chamber 10106 is cut off from the source passage, and the source necessary for the epitaxial growth exists only on the epitaxial growth surface.
PolyGaAs is prevented from depositing and adhering to the wall surface of 106 and the like. Further, the source passage 10109 and / or the path of the second source of the front chamber 10110 is also blocked by the control rod or the surplus source is discharged, so that the deposition of polyGaAs on the wall surface is prevented. It
Therefore, when discharging the first source, there is no deposition deposit or the source entangled with it, and it is possible to avoid mixing of the source.

When the temperature drops to, for example, 830 degrees Celsius, the temperature is lowered to a constant temperature to stop the epitaxial growth, and the control rod 10111 is slid to the right as shown in FIG. The exhaust source reservoir 101
Discharge to the left of 03.

Next, as shown in FIGS. 7G to 7I, the second source is formed into an epitaxial growth chamber 1011.
Inject to 0. The procedure and injection of the first source shown in FIGS. 7 (b) -7 (d) is similar, except that the source reservoir is slid to the left.

After the implantation, the temperature is lowered again in the state of FIG. 7 (i) to grow an AlGaAs layer on the GaAs epitaxial growth layer. The rate of temperature decrease may be 0.8 degrees Celsius / minute, for example.

When the temperature reaches, for example, 700 degrees Celsius, the control rod 10111 is slid to the right as shown in FIG. 7 (j), the second source is discharged to the right side of the exhaust source reservoir 10103, and the epitaxial growth step is completed. To do.

First source 11 used for GaAs growth
071, and the second source 1 used for AlGaAs growth
Since 1072 is discharged to the partitioned part of the source reservoir, it can be recovered and reused by adding necessary epitaxial growth raw materials.

The results of comparison between the case where the epitaxial growth is performed according to the present embodiment and the case where the epitaxial growth is performed under the same conditions using the conventional boat shown in FIG. 14 will be described.

Among the wafers after the epitaxial growth, the wafer closest to the source injection port was cleaved vertically to examine the thickness distribution of the wafer excluding the epitaxial growth layer.

A wafer having a thickness of 350 ± 10 μm was used in both the fifth embodiment and the conventional method, but in the conventional case, the lower edge is 42 μm with respect to the center.
(12%) It was thin. The lower edge is where the injected source first contacts. The source that is first injected is likely to be unsaturated at the source at the bottom of the source sump. Since the unsaturated portion of the source was implanted first, it is believed that the wafer was thinned as a result of etching the wafer during implantation. On the other hand, in the growth method according to the present embodiment, there is no difference in the wafer thickness between the center and the edge, and the 2 μm center within the wafer thickness tolerance is thick.

In order to examine the uniformity of the dopant, LEDs were prepared using 5 wafers and the emission wavelengths were compared.
Since a GaAs LED using Si as a dopant emits light between impurity levels, the emission wavelength depends on the Si concentration of the dopant.

The LED manufactured by epitaxial growth according to this embodiment had an average wavelength of 938 nm, and the difference between the maximum and minimum was 4 nm. On the other hand, LE by the conventional method
D had the same average wavelength, but the maximum and minimum difference was 11 nm
It was shown that the dopant was added non-uniformly.

The degree of source mixing was examined from the Al mixed crystal ratio of the AlGaAs layer epitaxially grown with the second source. The wafers on the left side (upstream side of the source implantation), the center, and the right side (downstream side of the source implantation) of the epitaxial growth chamber are cleaved, and A near the growth start interface of AlGaAs is cleaved.
The l mixed crystal ratio was measured by photoluminescence. In the present embodiment, the value was 0.30 as set, whereas in the conventional method, the values were 0.28, 0.21, and 0.11 from the left side, which were lower than the set value.

The decrease in the Al mixed crystal ratio is caused by the first
It shows that the source was mixed with the second source for growing AlGaAs. Further, it is considered that a large degree of decrease in the downstream side of the source injection by the conventional method indicates that the first source remaining in the source passage flowed while being absorbed when the second source was injected. . (6) Epitaxial growth method and apparatus therefor according to the sixth embodiment FIG. 8 shows an epitaxial growth apparatus according to the sixth embodiment. This apparatus includes source passages 2091 and 2020 connecting the source reservoir 2202 and the epitaxial growth chamber 2206.
A front chamber 2210 is provided between 92. However, a control rod that blocks the front chamber 2210 and the epitaxial growth chamber 2206 is not provided.

FIG. 8A shows the state before the epitaxial growth, and the source reservoir 2202 stores the epitaxial growth source 2207. When performing epitaxial growth, slide the source reservoir 2202 to the left,
The source is injected into the epitaxial growth chamber 2206 via the front chamber 2210.

Although the sauce flows into the front chamber 2210 and temporarily stays, it is made uniform by the self-stirring by the inflow. In order to lengthen the residence time and improve the stirring effect, it is desirable that the cross-sectional area of the source passages 2208 and 2091 in front of the front chamber 2210 be smaller than that of the source passage 2092 downstream of the front chamber 2210. (7) Epitaxial growth method and apparatus therefor according to the seventh embodiment FIG. 9 shows the configuration of the apparatus according to the seventh embodiment. In this apparatus, a front chamber 3310 is provided on the surface of the boat body 3301, and the source inflow from the front chamber 3310 to the epitaxial growth chamber 3306 is controlled by the movement of the source reservoir. A part 3023 of the bottom of the source reservoir 3302 is the front chamber 3
It has reached the bottom of 310.

FIG. 9A shows the state before the epitaxial growth. An epitaxial growth source 3307 is stored in the source reservoir 3302. When performing the epitaxial growth, the source reservoir 3302 is slid to the left to bring it to the state shown in FIG. 9B. That is, the outlet 3308 of the source reservoir is opened to the front chamber 3301, and the part 3023 of the source reservoir blocks the outlet 3308 of the source reservoir and the source passage 3309. In this state, the source 3307
Flows into the front chamber 3310 and is homogenized by stirring by the inflow, but does not flow into the epitaxial growth chamber 3306. If you slide the sauce reservoir further to the left,
As shown in (c), the front chamber 3310 communicates with the source passage 3309, and the source is injected into the epitaxial growth chamber 3306.

In the sixth embodiment, since the source is injected into the front chamber and the source is injected into the epitaxial growth chamber at the same time, the source may flow into the epitaxial growth chamber before being completely homogenized. . On the other hand, in the present embodiment, since the timing of injecting the source from the front chamber 3310 to the epitaxial growth chamber 3306 can be freely controlled, the epitaxial growth can be performed using the completely uniform source.

When the source reservoir 3302 is returned to the right from the state shown in FIG. 9B, the liquid level of the source transferred to the front chamber 3301 rises. Front chamber 3310 and source passage 33
The source can be forcibly stirred by moving the source reservoir from side to side while the 09 is blocked by a part of the source reservoir 3023.

By placing a raw material for an epitaxial growth source, for example, GaAs single crystal in GaAs epitaxial growth, in the front chamber 3310, even if the source in the source reservoir is unsaturated, a saturated solution can be prepared in the front chamber 3310. it can. (8) Epitaxial growth method and apparatus therefor according to the eighth embodiment FIG. 10 shows the configuration of an apparatus according to the eighth embodiment of the present invention. In this device, a first source 4071 and a second source 4072 are provided in different source passages 4091.
And 4092.

The control rod 4411 shuts off the source passage 4092, and does not directly have a function of discharging the source remaining in the first source passage 4091 to prevent deposition and adhesion from the first source. . However, by injecting the second source from a source passage different from that of the first source, it is possible to prevent the first source from being mixed. (9) Epitaxial growth method and apparatus therefor according to the ninth embodiment This embodiment relates to a semiconductor liquid phase epitaxial growth apparatus using a dipping method.

The basic structure of this device is as shown in FIG. This apparatus comprises a high temperature soaking unit 102 and a vertical heating furnace 101 having a low temperature unit 103 above the high temperature soaking unit 102,
A gas supply system 104 for supplying a reducing gas, an inert gas and a vacuum to the heating furnace 101, a wafer holder 105 for holding a plurality of wafers, a mechanism 106 for vertically moving the wafer holder, and a high temperature uniform temperature inside the heating furnace. Source reservoir 107 installed in the heating unit 102 and source 1 stored in the source reservoir
08 and.

FIG. 11 shows an example of the heater 109.
The structure of the 5-stage furnace which has five is shown. However, the number of heaters is not limited, as long as the high temperature soaking section 102 and the low temperature section 103 can be obtained. The low temperature portion 103 is shown as a constant temperature region, but this portion is the wafer holder 1
05 and preheating and cooling of the wafer,
For example, there may be some inclination as shown by the dotted line.

Japanese Unexamined Patent Publication No. 60-11571 discloses a method of keeping a wafer in a low temperature area outside the furnace. However, the temperature outside the furnace cannot be controlled by the furnace, and the temperature gradient is large. Therefore, thermal stress may be applied to the wafer to cause crystal defects. Therefore, such a situation can be avoided by providing a low temperature part capable of temperature control in the furnace as in the present embodiment.

Here, when the wafer is lowered from the standby position of the low temperature wafer to the high temperature epitaxial growth position, it is necessary to move the wafer at a constant speed or less in order to avoid a rapid temperature change. This speed is determined by the size of the wafer and the temperature gradient in the part where the wafer is moved.The smaller the wafer and the smaller the temperature gradient, the faster the wafer can be moved to the epitaxial growth position, resulting in the time required for the epitaxial growth process. Can be shortened.

Therefore, it is preferable that the temperature of the low temperature standby portion of the wafer is high in terms of process time, and it is particularly important that the temperature of the standby position is stable in terms of reproducibility of production.

Since the temperature outside the furnace is not stable because it is directly affected by outside air, it is desirable to have a controlled low temperature part inside the furnace. Since As vaporization from the substrate becomes remarkable from around 700 ° C., if the temperature of the low temperature part is controlled to 500 to 600 ° C., the process time can be minimized while avoiding the thermal deterioration of the substrate.

FIG. 11 shows two source reservoirs 107 mounted on the source reservoir 113. The source reservoir 107 can be rotated by a driving mechanism 114 to move an arbitrary source reservoir directly below the wafer holder. One of the features of the present embodiment is that a plurality of source reservoirs are provided and a mechanism for moving an arbitrary source reservoir to a position directly below the wafer holder is provided.

With this structure, the wafer can be put into an arbitrary source for epitaxial growth, so that epitaxial growth can be sequentially performed using a plurality of sources to obtain a plurality of epitaxial growth layers. The drive of the source reservoir is not limited to rotational movement,
A linear motion or the like may be used as long as it can move a plurality of source reservoirs directly below the wafer holder.

The drive mechanism 114 also has a vertical drive mechanism, and the source 108 can be taken out from the lower side of the heating furnace 101.

Another feature of this embodiment is that it has a mechanism for stirring the sauce. FIG. 11 shows the stirring blade 115 and the stirring blade driving mechanism 116 that are lowered into the source 108. By rotating the stirring blade 116, the sauce can be stirred. The stirring is not limited to rotation, and may be vertical movement, horizontal movement, or a combination thereof. The shape of the stirring blade can be any shape, such as a plate shape or a propeller shape, according to the movement of the blade. Alternatively, it is not limited to the shape of the blade, and an object having a predetermined volume may be moved in and out of the sauce by using vertical movement, and the liquid surface of the sauce may be moved up and down to stir.

One of the other characteristics of this embodiment is that the semiconductor material as a solute is supplied to the source and saturated at a high temperature for epitaxial growth. FIG. 11 shows a semiconductor material 1 as its specific mechanism.
17 and the mechanism 118 for driving it up and down. However,
A mechanism for holding the semiconductor material 117 is omitted in FIG. 11.

By stirring and supplying the source using the apparatus according to this embodiment, the following effects can be obtained.

In order to carry out liquid phase epitaxial growth, it is necessary that the source is saturated when the wafer is put into the source. If the source is unsaturated, the wafer will melt into the source when it is placed in the source. On the other hand, when the wafer is supersaturated, the solute deposited before the wafer is placed covers the surface of the source, which is an obstacle when the wafer is put into the source by the dipping method. Therefore, it is calculated that the source is saturated with the solute semiconductor material at the temperature at which the epitaxial growth is started, and a predetermined solvent metal and solute are put into the source reservoir at room temperature to raise the temperature. However, the source becomes unsaturated at the start of epitaxial growth or conversely becomes supersaturated due to undissolved solute, an error in temperature control, an error between the calculated solubility value and an actual value.

In liquid phase epitaxial growth, the metal solute has a larger specific gravity, so that the solute floats on the surface of the solvent. Therefore, in order to dissolve all the solutes in the solvent, the solutes need to diffuse into the solvent, which requires a long time. Further, a concentration difference is likely to occur between the vicinity of the surface of the source and the inside. By stirring the source according to the above-described embodiment, the movement of the solute is promoted, the undissolved solute is prevented, and the source is made uniform. Further, the source is heated and then the source is made uniform, and the epitaxial growth layer It has the effect of shortening the time until

The source supply mechanism has an effect of preventing solute precipitation before epitaxial growth due to oversaturation. The amount of solute that can reliably stay unsaturated at the temperature at which epitaxial growth starts is added to the solvent in advance at room temperature, the temperature is raised to the epitaxial growth start temperature, and then the semiconductor material that is the solute is put into the source. Can be dissolved in the solute until the solute is saturated. By performing such an operation at a constant temperature or while raising the temperature, it is possible to prevent the source from being oversaturated and the solute to be deposited on the surface. The temperature at the end of solute supply is preferably the same as the epitaxial growth start temperature so that precipitation does not occur after the solute supply and before the epitaxial growth starts.

The solute supply to the source can be completed in a short time by performing the source while stirring. Further, it is desirable that a solute semiconductor material is attached to the stirring blade, or that the stirring blade itself or a part thereof is made of a solute semiconductor material. For example, in the case of GaAs epitaxial growth using a Ga solvent, the stirring mechanism and the source saturated supply can be used as a mechanism by using a stirring blade made of GaAs.

In the present apparatus, after the epitaxial growth is completed once, the wafer can be removed from the wafer holder, a new wafer can be mounted on the wafer holder, and the epitaxial growth can be repeated using the source as it is. The source supply mechanism can be used to supply the consumed solute before the second and subsequent epitaxial growths.

When performing the first epitaxial growth,
By dipping the wafer holder into the source, the liquid level of the source rises, and when epitaxial growth is performed in this state, the polycrystal is deposited and adheres to the wall surface of the source reservoir to a position higher than the normal source liquid level. In this case, as described above, by adopting a method of putting the stirring object in and out of the source and stirring, it is possible to immerse the precipitate at a high position in the source and dissolve the precipitate for reuse. .

Next, the infrared L of the structure shown in FIG.
In order to manufacture epitaxially grown wafers for ED,
Using the apparatus shown in FIG. 11, Ga is used as a source solvent, GaAs and Si are used as solutes, and a specific apparatus configuration and growth method for obtaining a GaAs epitaxial growth layer doped with Si will be described. .

The heating furnace 101 is a vertical five-stage heater furnace. The length of the furnace body is 150 cm, and the inner diameter of the quartz reaction tube installed in the furnace is 30 cm. The high temperature soaking section 102 has a length of 30 cm within a range of ± 0.5 degrees Celsius, and the temperature of the low temperature section 103 when the high temperature soaking section is heated to 1000 degrees Celsius is 3
It has a slope of 482 to 514 degrees Celsius in the range of 0 cm.

The source reservoir 113 is made of quartz having a diameter of 28 cm, and its drive shaft is a quartz tube having a diameter of 12 cm.
The drive mechanism 114 rotates the source reservoir 113 by 180 degrees.

As shown in FIG. 13, the source reservoir 107 has a structure in which two source reservoirs 1071 and 1072 are integrated. The source reservoir 107 is made of carbon and has a width of 17.5c so that the diagonal line is about 28 cm.
It has a rectangular parallelepiped shape of m, depth 21.9 cm, and height 20 cm. In this rectangular parallelepiped, width 8cm, depth 20.9c
Two rectangular parallelepiped holes each having a depth of m and a depth of 19 cm are provided. The two holes serve as a first source reservoir 1071 and a second source reservoir 1072. The thickness of the outer wall of the source reservoir and the wall between the source reservoir is 0.5 cm, and the thickness of the bottom is 1 cm.

The stirring blade 115 has a width of 5.6 cm and a length of 8
cm, 0.8 cm thick quartz plate, and the rod that drives the blade is a 1.4 cm diameter quartz rod. Drive mechanism 116
Is for rotating a stirring blade through a quartz rod and moving it up and down.

The semiconductor material 117 is a disc-shaped GaAs single crystal having a diameter of 5 cm and a thickness of 2.4 cm, and the driving rod has a diameter of 1.
It is a 4 cm quartz rod. The drive mechanism 118 can also move the GaAs disk up and down via a quartz rod and further rotate it.

The gas system 104 comprises hydrogen in the heating furnace 101,
Nitrogen and a mixed gas of both are supplied, and a vacuum is drawn.

The wafer holder 105 is made of carbon and has the structure shown in FIG. 2 by stacking the holder plates 14c shown in FIG. The material of the wafer holder needs to have thermal resistance and chemical resistance to the epitaxial growth source, and is preferably a material that can be processed with high precision. Alternatively, a base material whose surface is coated with another material may be used. Specifically, in addition to carbon, quartz, silicon carbide, sapphire, and other ceramics can be used.

Next, the result of forming the epitaxial growth layer based on the above embodiment will be described.

The first source reservoir was used for GaAs epitaxial growth, and contained 7500 g of metallic Ga as a solvent, 1197 g of polycrystalline GaAs as a solute, and 22.5 g of silicon pieces. The second source reservoir is used for epitaxial growth of AlGaAs, and contains 7500 g of metallic Ga as a solvent and 238.1 g of polycrystalline GaAs as a solute.
36.7g of Al wire was added.

A stack of 49 holder plates is housed in a box-shaped cassette and integrated into a wafer holder with a diameter of 62 m.
After 98 pieces of Si-doped N-type GaAs wafers having a thickness of 300 m and a thickness of 300 μm were mounted on the respective holder plates and the covers were mounted, the wafer holders were held in the low temperature part in the heating furnace.
Further, the conductor material 117 and the stirring blade 115 were placed in the low temperature part.

The position of the source reservoir 113 was adjusted so that the first source reservoir was directly below the stirring blade and the semiconductor material.

In this state, the inside of the furnace was once evacuated, then the inside of the furnace was filled with hydrogen, and after the pressure became normal, 5 liters of hydrogen per minute was kept flowing.

At the same time as the atmospheric pressure was reached, the temperature of the furnace was started to rise, and the temperature reached 915 degrees Celsius at which epitaxial growth started 2 hours later.

The GaAs epitaxial growth source in the first source reservoir has a calculated Ga of 30 g at 915 degrees Celsius.
As is unsaturated. Upon reaching 915 degrees Celsius, the semiconductor material 117 was lowered into the GaAs epitaxial growth source 108 in the first source reservoir and spun for 30 minutes at a rate of 15 revolutions per minute. In this step, GaAs and Si initially stored in the source reservoir were completely dissolved, and the weight of the semiconductor material 117 was measured after the epitaxial growth was completed. As a result, 32.5 g was melted into the source.

After stirring for 30 minutes, the semiconductor material 117 was pulled up, and the source reservoir 113 was rotated half a turn. By this rotation, the GaAs epitaxial growth source reservoir was placed directly below the wafer holder 105, and the AlGaAs epitaxial growth source reservoir was placed directly below the stirring blade 115.

Next, the wafer holder was lowered in the source reservoir to a position where it did not come into contact with the source liquid surface, and was left at that position for 10 minutes. This position is inside the soaking zone, and the temperatures of the wafer and the source are almost the same.

After 10 minutes, the wafer holder was lowered into the source, the temperature was lowered at a rate of 0.4 ° C./min to start epitaxial growth, and the wafer holder was pulled up at 860 ° C. to complete the epitaxial growth.

During this time, GaAs is epitaxially grown on the wafer. Since the dopant Si naturally inverts, the N-type GaAs epitaxial growth layer grows in the first half of the epitaxial growth and the P-type GaAs epitaxial growth layer grows in the latter half below the inversion temperature of about 880 degrees Celsius.

During the GaAs epitaxial growth, AlGaA in the second source reservoir immediately below the stirring blade 115.
It was lowered into the s epitaxial growth source and rotated at a speed of 15 times per minute to completely dissolve the source solutes AlGaAs and Al.

At the same time when the GaAs epitaxial growth was completed at 860 degrees Celsius, the temperature was kept at 860 degrees Celsius.
The stirring blade 115 and the wafer holder 105 were pulled up from the respective source reservoirs, and the source reservoir base 113 was rotated again by half rotation to exchange the positions of the source reservoirs.

During the source exchange, the wafer holder was taken out of the source reservoir, but kept in the soaking region in the furnace. The reason why the wafer holder is not pulled up to the low temperature part inside or outside the furnace is to keep the wafer holder at the same temperature as the source so that preheating before the next epitaxial growth start can be omitted and the epitaxial growth process can be simplified and speeded up. is there. By using a wafer holder having a high degree of airtightness such as the wafer holder according to the above-described embodiment, thermal deterioration can be avoided even when the wafer is held at a high temperature.

Subsequently, the wafer holder was dipped in the source of the second source reservoir, and AlGaAs epitaxial growth was performed.

The temperature of the source was lowered at a rate of 0.4 degrees Celsius per minute, and the wafer holder was raised to a low temperature at 820 degrees Celsius to complete the epitaxial growth.

In this step, the AlGaAs epitaxial growth layer was grown on the GaAs epitaxial growth layer.

After the epitaxial growth was completed, the temperature of the furnace was lowered, and when the temperature of the low temperature part fell below 200 degrees Celsius, the inside of the furnace was replaced with nitrogen, and the wafer holder and the wafer were taken out.

The structure of the wafer obtained through the above steps is as shown in FIG. N-type GaAs wafer 91
A 60 μm thick N-type GaAs epitaxial growth layer 92.40 μm P-type GaAs epitaxial growth layer 9
A non-doped AlGaAs layer (Al mixed crystal ratio 0.7) 94 of 3.10 μm is grown. The surface after the epitaxial growth was smooth.

When this wafer is etched with hydrofluoric acid at 50 degrees Celsius, only the AlGaAs layer 94 is etched. Etching was performed to obtain an epitaxially grown wafer having the structure shown in FIG.

Of the 98 wafers having the structure shown in FIG. 12B, 25 wafers every 3 wafers were cleaved and stain etching was performed to obtain GaA of 5 points on each wafer.
The s epitaxial growth layer was examined. The N-type GaAs layer has an average thickness of 58.4 μm and a standard deviation of 4.2 μm.
The aAs layer has an average thickness of 38.8 μm and a standard deviation of 2.9.
was μm.

The average thickness was in agreement with the designed values of 60 μm and 40 μm, and the standard deviation was remarkably improved as compared with the film thickness accuracy of the conventional epitaxial growth method of about ± 30%.

As described above, Si-doped GaA with Ga as a solute
The epitaxial growth of s and non-doped AlGaAs was explained as an example, but GaAs and A using other dopants were used.
It can also be applied to liquid phase epitaxial growth of 1GaAs, GaP and other compound semiconductors, and further to liquid phase epitaxial growth of Si using Sn or Ga as a solvent.

[0159]

The wafer holder of the present invention holds the wafers face-to-face and covers the periphery of the wafer to limit the presence of unnecessary epitaxial growth sources in the periphery of the wafer. It is possible to prevent precipitation, suppress the diffusion of the source solute from the periphery of the wafer to the edge of the wafer, and obtain an epitaxial growth layer having a uniform thickness and composition.

Also, the epitaxial growth apparatus of the present invention is
By making the epitaxial growth source uniform and preventing unnecessary sources or polycrystalline precipitation from remaining in the passage for supplying the source to the wafer holder, it is possible to achieve uniform and controllability especially when performing liquid phase epitaxial growth of two or more layers. A good epitaxial growth layer can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view and a bottom view showing a configuration of a wafer holder according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view and a bottom view showing the configuration of a wafer holder according to a second embodiment of the present invention.

FIG. 3 is a vertical sectional view showing a positional relationship between a wafer and a pouring / discharging port in the same wafer holder.

FIG. 4 is a perspective view showing a structure of a wafer holder according to a third embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing the steps of storing a wafer using the same wafer holder in each process.

6A and 6B are a perspective view and a vertical sectional view showing the structure of a wafer holder according to a fourth embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view showing an epitaxial growth method and apparatus therefor according to a fifth embodiment of the present invention.

FIG. 8 is a vertical sectional view showing an epitaxial growth method and apparatus therefor according to a sixth embodiment of the present invention.

FIG. 9 is a vertical sectional view showing an epitaxial growth method and apparatus therefor according to a seventh embodiment of the present invention.

FIG. 10 is a vertical sectional view showing an epitaxial growth method and apparatus according to an eighth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view showing an epitaxial growth method and apparatus according to a ninth embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view showing the structure of a wafer obtained by the same epitaxial growth method.

FIG. 13 is a vertical cross-sectional view showing the structure of a source reservoir in the epitaxial growth apparatus.

FIG. 14 is a vertical cross-sectional view showing the configuration of a conventional epitaxial growth apparatus.

FIG. 15 is a vertical cross-sectional view showing the configuration of another conventional epitaxial growth apparatus.

FIG. 16 is a vertical sectional view showing an epitaxial growth method by a conventional dipping method.

FIG. 17 is a vertical cross-sectional view showing an epitaxial growth method by another conventional dipping method.

FIG. 18 is a vertical cross-sectional view showing a positional relationship between a wafer and a source when epitaxial growth is performed by a conventional epitaxial growth method.

[Explanation of symbols]

11, 11a, 11b, 11c Wafer holder 12, 12a, 12b, 12c Cover 13 Pouring port 14, 14a, 14b, 14c Wafer holder part 15, 105, 10105, 5505 Wafer 16 Gas vent port 17 Step part 18 Tapered part 19 Presser plate 91 N-type GaAs wafer 92 N-type GaAs epitaxial growth layer 93 P-type GaAs epitaxial growth layer 94 Non-doped AlGaAs layer 101 Heating furnace 102 High temperature soaking part 103 Low temperature part 104 Gas supply system 105 Wafer holder 106 Vertical driving mechanism 107 Source reservoir 1071 1 source reservoir 1072 second source reservoir 108 source 109 heater 110 wafer 111 spacer 112 groove 113 source reservoir 114 driving mechanism 115 stirring blade 116 stirring blade driving mechanism 117 semiconductor material 1 8 drive mechanism 1081～1085,2208,3308,5081～
5085, 6081, 6082 Source outlets 1109, 2091, 2092, 3309, 4409,
4091,4092,5509 Source passage 1110,3310 Front chamber 1111,4411 Control rod 10101,3301,5501 Main body 10102,2202,3302,3023,550
2,6602 Source reservoir 10103,5503 Exhaust source reservoir 10104,5504 Partition plate 10106,3306,5506 Epitaxial growth chamber 1071,1072,2207,3307,4071,
4072, 5507, 6071, 6072 Epitaxial growth source

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-60-21897 (JP, A) JP-A-60-115271 (JP, A) JP-A-62-83398 (JP, A) JP-A-2- 302391 (JP, A) JP 5-279193 (JP, A) JP 5-291157 (JP, A) JP 7-69784 (JP, A) JP 8-151293 (JP, A) 62-103245 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C30B 1/00-35/00 H01L 21/208 EUROPAT (QUESTEL)

Claims (16)

(57) [Claims] 1. A wafer storage space for holding the back surfaces of at least one set of semiconductor wafers in contact with the inner side walls so that the front surfaces face each other with a predetermined gap, and a source is poured into and discharged from the wafer storage space. A holder main body provided with a pouring outlet, or an inlet for injecting a source into the wafer storage space and an outlet for discharging the source from the wafer storage space, and a holder cover for covering an opening surface of the holder main body, A wafer holder comprising: 2. A predetermined gap is provided between the outer edge of the semiconductor wafer and the outer edge of the semiconductor wafer, which is close to the outer edge of the semiconductor wafer in the wafer housing space of the holder body, and thereby the semiconductor wafer is provided. 2. The wafer according to claim 1, wherein the source that enters the outer edge portion of the wafer is limited to a predetermined amount, and diffusion of the epitaxial growth raw material contained in the source to the edge portion of the semiconductor wafer is suppressed near the outer edge portion. holder. 3. The wafer holder according to claim 2, wherein the gap between the wall in the wafer storage space and the outer edge of the semiconductor wafer is 4.9 mm or less. 4. A semiconductor wafer except for a portion where the outer edge of the semiconductor wafer and the outer edge of the semiconductor wafer in the wafer housing space of the holder body are close to each other, except for the portion where the pouring port or the pouring port and the pouring port exist. Between the entire circumference of the outer edge of
4. The wafer holder according to claim 1, wherein the semiconductor wafer is held with a predetermined gap. 5. A taper portion or a step portion is provided on a wall of the holder main body, which is close to the outer edge of the semiconductor wafer in the wafer storage space, so that the diameter of the rear surface side of the semiconductor wafer is larger than the diameter of the front surface side. The wafer holder according to any one of claims 1 to 4, wherein the wafer holder is provided. 6. The taper portion or the step portion provided on the wall of the wafer housing space of the holder body has a minimum diameter of 4 mm or less smaller than the diameter of the semiconductor wafer. Wafer holder described. 7. The taper portion or the step portion provided on the wall of the wafer housing space of the holder body has a minimum diameter that is equal to or larger than a diameter of a portion of the semiconductor wafer where chamfering is not performed. The wafer holder according to claim 5. 8. A U-shaped or semicircular pocket is formed in the semiconductor wafer storage space of the holder body so as to conform to the outer peripheral shape of the semiconductor wafer, and the semiconductor wafer is opened from the opening side. 2. The holder cover, which is inserted and held in a wafer storage space and covers the opening surface of the holder body, has a semicircular surface so as to conform to the outer peripheral shape of the semiconductor wafer. 7. The wafer holder according to any one of 7. 9. A disk-shaped wafer holding plate, and a U-shaped or semi-circular groove portion provided so as to surround a peripheral region of the wafer holding plate excluding an opening surface, and at least one set of Holder plates that hold the backsides of the semiconductor wafers in contact with both sides of the wafer holding plate so that the outer edges of the semiconductor wafers are fitted into the grooves and held back to back, and a U-shape that fits the outer periphery of the semiconductor wafer Or a holder cover having a semicircular groove portion, which covers the opening surface of the wafer holding plate and holds the outer edge of the semiconductor wafer held by the wafer holding plate by being fitted into the groove portion and holding the outer edge of the semiconductor wafer. Two sets are provided, and by stacking the holder plate and the holder cover, the respective surfaces of two semiconductor wafers face each other with a predetermined gap. Wafer holder, characterized in that it is urchin retained. 10. A wafer holding plate and a U-shaped or semi-circular groove portion provided so as to surround a peripheral region of the wafer holding plate excluding an opening surface thereof. A holder plate in which the outer edge of the semiconductor wafer is fitted and held in the groove while being in contact with the inner bottom surface of the wafer holding plate; and a U-shaped or semicircular groove adapted to the outer periphery of the semiconductor wafer, At least two sets of a holder cover, which covers the opening surface of the wafer holding plate and holds the outer edge of the semiconductor wafer held by the wafer holding plate by being fitted into the groove portion, are provided. The other holder plate is placed on the upper surfaces of the pair of held holder plates and the holder cover so as to sandwich the other semiconductor wafer. Wafer holder, wherein a surface of, respectively is held so as to face at a predetermined distance. 11. An inlet for injecting a source and an outlet for exhausting the source are provided in the groove of the wafer holding plate, and the inlet and the outlet are held by the wafer holding plate. The wafer holder according to claim 9 or 10, wherein a step having a thickness that is approximately half the thickness of the semiconductor wafer or more is formed. 12. The predetermined gap between two semiconductor wafers held by at least two sets of the wafer holding plate and the holder cover so that their surfaces face each other, and the predetermined distance is about 0.
10. The length is 3 mm to 5.0 mm.
The wafer holder according to any one of 1 to 11. 13. A source reservoir for accommodating a source used for liquid phase epitaxial growth, and a wafer holder for holding a semiconductor wafer, wherein the back surfaces of at least one set of semiconductor wafers are brought into contact with inner side walls and the surfaces are spaced apart by a predetermined distance. It has a wafer storage space that holds it so as to face each other, and a pouring port for pouring and ejecting a source into the wafer storage space, or a pouring port for injecting a source into the wafer storage space and a source for discharging the source from the wafer storage section. A wafer holder having a holder main body provided with a discharge port, and a holder cover for covering the opening surface of the holder main body, and an epitaxial growth for accommodating a semiconductor wafer which is located below the source reservoir and is held by the wafer holder. A chamber, a source passage provided between the source reservoir and the epitaxial growth chamber, A front chamber provided in a part of the source passage, and when the source stored in the source reservoir is introduced into the epitaxial growth chamber through the source passage, the source in the front chamber is An epitaxial growth apparatus characterized by being agitated. 14. A high temperature soaking region which is heated by a heating means to form a substantially uniform temperature distribution, and a low temperature region which is located above the high temperature soaking region and which is lower in temperature than the high temperature soaking region. A heating furnace having, a gas supply means for supplying a reducing gas and / or an inert gas to the heating furnace, a solute containing a semiconductor material used for epitaxial growth, which is installed in the high temperature soaking region in the heating furnace. And a wafer holder for holding a semiconductor wafer, wherein a back surface of at least one set of semiconductor wafers is brought into contact with an inner side wall so that the surfaces face each other with a predetermined gap. A holding / holding space for holding the wafer, and a pouring / pouring port for pouring / discharging the source into / from the wafer storage space, or an injection port for pouring the source into the wafer storage space, and A holder main body provided with an outlet for discharging the source from the wafer storage part, a wafer holder having a holder cover for covering an opening surface of the holder main body, and the wafer holder being moved vertically in the heating furnace, Wafer holder moving means for immersing the semiconductor wafer held by the wafer holder in the source in the source reservoir when performing epitaxial growth, and a stirring blade for stirring the source in the source reservoir,
And a stirring blade moving unit that moves the stirring blade in the vertical direction to move the stirring blade into and out of the source. 15. A wafer storage space for holding a plurality of semiconductor wafers in a wafer holder, wherein a back surface of at least one set of semiconductor wafers is brought into contact with an inner sidewall so that the front surfaces thereof are opposed to each other with a predetermined gap. And a holder main body provided with an inlet / outlet for injecting / injecting a source into the wafer storage space, or an inlet for injecting a source into the wafer storage space and an outlet for discharging the source from the wafer storage space. , Using a wafer holder having a holder cover that covers the opening surface of the holder body,
A step of holding a semiconductor wafer, a step of storing the semiconductor wafer held by the wafer holder in an epitaxial growth chamber, a step of flowing a reducing gas and / or an inert gas into the epitaxial growth chamber, and the epitaxial growth chamber is predetermined. Heating to a temperature, the source stored in the source reservoir is introduced into the front chamber and stirred, and then the source is introduced into the epitaxial growth chamber to bring the source into contact with the semiconductor wafer; I will lower the temperature in the room,
A semiconductor liquid phase epitaxial growth method comprising: a step of performing epitaxial growth on a semiconductor wafer; and a step of discharging a source in the epitaxial growth chamber to end the epitaxial growth. 16. A wafer storage space for holding a plurality of semiconductor wafers in a wafer holder, wherein at least one set of semiconductor wafers is brought into contact with an inner back surface of a side wall and is held so that its front surfaces face each other with a predetermined gap. And a holder main body having an inlet / outlet for injecting / discharging a source into / from the wafer storage space, or an inlet for injecting a source into the wafer storage space and an outlet for discharging the source from the wafer storage space. And a step of holding a semiconductor wafer by using a wafer holder having a holder cover for covering the opening surface of the holder body, and a high temperature soaking region heated by a heating means to form a substantially uniform temperature distribution, Within the low temperature region in the heating furnace having a low temperature region located above the high temperature soaking region and having a lower temperature than the high temperature soaking region, A step of holding the wafer holder holding a conductor wafer; a step of flowing a reducing gas and / or an inert gas into the heating furnace; and a high temperature soaking region in the heating furnace at a predetermined temperature Heating by a heating means, lowering the wafer holder from the low temperature region to a position of the high temperature soaking region, and raising the temperature of the wafer holder and the semiconductor wafer to the predetermined temperature, the wafer holder and the semiconductor wafer Of the solute containing the semiconductor material used for epitaxial growth is placed in the source in the source reservoir containing the source dissolved in the solvent containing the metal, and the temperature of the high temperature soaking region is lowered. , A step of performing epitaxial growth on a semiconductor wafer, and pulling out the wafer holder from the source to perform epitaxy. Semiconductor liquid phase epitaxial growth method characterized by comprising the steps of: terminating the catcher Le growth,.