JP6606700B2 - Single crystal manufacturing apparatus, housing member for single crystal manufacturing apparatus, and method for manufacturing single crystal - Google Patents

Description

  The present invention relates to a single crystal manufacturing apparatus, a housing member for a single crystal manufacturing apparatus, and a method for manufacturing a single crystal.

Silicon carbide has excellent heat resistance, high breakdown voltage, wide energy band gap,
In addition, since it has excellent performance such as high thermal conductivity, it can be applied to high power power devices, high temperature resistant semiconductor elements, radiation resistant semiconductor elements, high frequency semiconductor elements, and the like. Since silicon is approaching the limit of performance improvement from the physical property limit of the material itself, silicon carbide that can take a physical property limit larger than silicon has attracted attention. In recent years, power electronics technology using silicon carbide materials has been expected as an energy-saving technology for reducing energy loss during power conversion, which is a measure against global warming.
Research and development of silicon carbide single crystal growth technology has been vigorously promoted as the basic technology, and it is an urgent task to establish a large-diameter and long-length technology mainly from the viewpoint of reducing manufacturing costs in order to promote practical application. ing.

  As a method for growing a silicon carbide single crystal, a sublimation recrystallization method is widely used. In this sublimation recrystallization method, a seed crystal is fixed to a pedestal arranged in a crucible, a silicon carbide raw material disposed on the bottom of the crucible is heated to 2000 ° C. or more to generate sublimation gas, and the sublimation gas is tens of A silicon carbide single crystal is grown on the seed crystal by recrystallization on a seed crystal at a low temperature of several hundred degrees Celsius.

  Conventionally, in order to obtain a large-diameter and high-quality silicon carbide single crystal wafer efficiently and at low cost, a method for producing a longer silicon carbide single crystal has been desired.

  As a method for producing a long silicon carbide single crystal, a silicon carbide single crystal is grown on a silicon carbide seed crystal, and a portion of the silicon carbide single crystal that has grown larger than the diameter of the silicon carbide seed crystal is processed and removed. The silicon carbide seed crystal and the silicon carbide single crystal on the silicon carbide seed crystal are covered with a protective material except for the growth surface, and the silicon carbide single crystal further covered on the growth surface of the silicon carbide seed crystal and the silicon carbide single crystal covered with the protective material. There is known a method for lengthening the substrate by growing it (hereinafter sometimes referred to as “additional growth”) (Patent Document 1).

  In addition, as a method of producing a long silicon carbide single crystal while reducing polycrystals growing around the pedestal, etc., a guide is provided so that the sublimation gas of the raw material is guided to the surface of the silicon carbide seed crystal to promote crystal growth. A method of using a member (gas flow control member) (Patent Document 2), or forming a gas passage between a hole through the guide member to the inner wall side of the crucible or between the raw material side end of the guide member and the inner surface of the crucible (Patent Document 3) has been proposed.

In addition, a crucible lower portion where the silicon carbide raw material is disposed, a crucible upper portion covering the crucible lower portion, and a pedestal disposed on a protrusion formed in the center of the crucible upper portion, the crucible upper portion is independent of the crucible lower portion. The method of maintaining the distance between the growth surface and the raw material surface by pulling up the seed crystal affixed to the pedestal by moving the crucible upper part upward as the crystal growth proceeds (Patent Document 4) has been proposed.
In addition, in order to solve the problem of promoting the growth rate of the single crystal in the hole of the guide member and the gas passage and the problem of the polycrystal growing on the crucible upper lid, the guide is not provided with a gas passage and is adjusted to the growth of the single crystal. The structure (patent document 5) which can open and close the hole part of a member is proposed.

  In addition, a guide member having a length in the growth direction sufficient to surround the entire side surface of the silicon carbide single crystal growing on the silicon carbide seed crystal is used, and the guide member is continuously or stepwise outside the crucible. A method of manufacturing a long silicon carbide single crystal without processing / removing a portion that has grown larger than the diameter of the silicon carbide seed crystal by growing a silicon carbide single crystal by sliding to Document 6) has been proposed. Further, in Patent Document 6, through the growth process of the silicon carbide single crystal, heat flows from the outside of the guide member toward the single crystal in the vicinity of the growth surface of the single crystal, and in the vicinity of the seed crystal side of the single crystal. There has been proposed a configuration in which a temperature gradient adjusting member is arranged around the guide member so as to generate a temperature gradient in which heat is released from the single crystal toward the outside of the guide member.

Japanese Patent No. 4219800 JP 2002-60297 A JP 2005-53739 A JP 2009-23880 A JP 2012-201584 A JP2012-240894A

  Although the methods disclosed in Patent Documents 2 to 5 are effective for increasing the length of a silicon carbide single crystal by one crystal growth, the length of the silicon carbide single crystal obtained by one crystal growth is long. There is a limit to scaling, and at present, additional growth (Patent Documents 1 and 6) is considered essential for further lengthening.

  In addition growth, it is necessary to cover a portion other than the growth surface of the silicon carbide single crystal grown on the silicon carbide seed crystal with a protective material to prevent sublimation of the material from the crystal during the growth process. Become. A portion of the silicon carbide single crystal that grows on the silicon carbide seed crystal grows larger than the diameter of the silicon carbide seed crystal (hereinafter sometimes referred to as “expanded growth portion”). Therefore, a step on the side surface occurs between the silicon carbide seed crystal and the silicon carbide single crystal, or between the silicon carbide single crystal grown first and the silicon carbide single crystal grown next. If the side surface is covered with a protective material with a large level difference, the protective material may break. In order to avoid this, it is necessary to process and remove this enlarged growth portion.

However, the process and removal process of the enlarged growth portion reduces the production efficiency, and there is a possibility that the silicon carbide single crystal is cracked in the process.
Therefore, it is desirable that the periphery of the silicon carbide seed crystal and the silicon carbide single crystal can be covered with a protective material without performing the processing and removing step of the enlarged growth portion.
Further, even if it is necessary to process and remove the enlarged growth portion, if the amount of the enlarged growth portion is small, the processing removal process of the enlarged growth portion can be completed in a short time.

  In this regard, the method disclosed in Patent Document 6 does not require the processing and removal step of the enlarged growth portion, or the amount of the enlarged growth portion is small, and the processing and removal step of the enlarged growth portion can be completed in a short time. However, only temperature control (temperature gradient adjusting member in Patent Document 6) sufficiently suppresses the growth of polycrystalline silicon carbide (see FIG. 12) formed between the guide member and the growth surface of the silicon carbide single crystal. As a result, it has been difficult to produce a high quality and long silicon carbide single crystal. Therefore, a method for preventing the formation of polycrystals between the guide member and the single crystal growth surface has been required.

  The present invention has been made in view of the above circumstances, and does not require a processing removal step of the enlarged growth portion of the single crystal, or at least shortens the time of the processing removal step, and is high quality and long. It is an object of the present invention to provide a single crystal manufacturing apparatus, a single crystal manufacturing apparatus housing member, and a single crystal manufacturing method capable of manufacturing a long single crystal.

The present invention provides the following means in order to solve the above problems.
(1) A single crystal production apparatus for producing a single crystal by growing a single crystal on a growth surface of a seed crystal arranged in a crucible,
A bottomed cylindrical accommodating member that is slidably held in the upper and lower directions on the upper lid of the crucible and can accommodate a seed crystal;
A guide member fixed to the side wall of the crucible and guiding the source gas to the seed crystal side,
The guide member has a cylindrical portion that is arranged so that at least an inner surface of an upper end portion thereof is substantially flush with an inner surface of the accommodating member in the vertical direction, and the upper end portion is a lower end surface of the accommodating member. Can be arranged so as to surround the growth surface side of the outer surface of the single crystal protruding downward from
The single crystal manufacturing apparatus characterized in that the gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member can be 0.1 to 1.0 mm at the time of manufacturing the single crystal.
(2) The single crystal manufacturing apparatus according to (1), further comprising a flange portion extending outwardly from the side wall substantially parallel to the upper lid at a lower end of the side wall of the housing member.
(3) The single crystal manufacturing apparatus according to (2), wherein the flange portion extends 4 to 10 mm outward from a side wall of the housing member.
(4) The gap between the outer surface of the single crystal and the inner surface of the upper end portion of the guide member surrounding the outer surface is 0.1 to 1.5 mm. (1) The single crystal manufacturing apparatus according to any one of (3).
(5) A bottomed cylindrical housing member capable of housing a seed crystal for a single crystal manufacturing apparatus, comprising a flange extending outward from the side wall at a lower end of the side wall. A storage member for a single crystal manufacturing apparatus.
(6) A method for producing a single crystal by growing a single crystal on a growth surface of a seed crystal disposed in a crucible,
A bottomed cylindrical housing member that contains a seed crystal so as to be slidable in the vertical direction on the upper lid of the crucible;
A guide member that is fixed to the side wall of the crucible and guides the source gas to the seed crystal side, and is arranged so that at least the inner surface of the upper end thereof is substantially flush with the inner surface of the housing member in the vertical direction. Using a guide member having a cylindrical portion,
The gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member is 0.1 to 1.0 mm,
A method for producing a single crystal, comprising: growing the single crystal in a state where the guide member is arranged so that an upper end portion of the guide member surrounds a growth surface side of the outer surface of the single crystal.
(7) The housing member is provided with a flange provided at the lower end (open end) of the side wall and extending outwardly from the side wall substantially parallel to the upper lid (6). A method for producing a single crystal as described in 1. above.

  According to the single crystal manufacturing apparatus of one aspect of the present invention, the crucible upper lid is slidably held in the vertical direction, and is fixed to the bottomed cylindrical housing member capable of housing the seed crystal, and the side wall of the crucible, A guide member that guides the source gas to the seed crystal side, and the guide member has a cylindrical portion that is arranged so that at least the inner surface of the upper end thereof is substantially flush with the inner surface of the housing member in the vertical direction At the same time, the upper end portion surrounds the growth surface side of the outer surface of the single crystal projecting downward from the lower end of the housing member, and there is no gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member. Since a structure capable of producing a single crystal with a thickness of 1 to 1.0 mm is adopted, gas can escape from this gap, so that deposition of polycrystals on the inner surface of the guide member can be suppressed. .

  By providing a gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member, gas can escape from the gap and deposition of polycrystals on the inner surface of the guide member can be suppressed, but the gas can escape. As a result, a dent or a step is formed on the outer surface of the single crystal in the vicinity of the gap during the growth, and a large number of macro defects are generated starting from this. In this specification, the macro defect is a defect having a diameter of about 10 to 500 μm, and as an example, there is a defect having a hollow inside (the “diameter” in this case can vary depending on the shape). Means the largest of the diameters). In addition, the macro defect may be a defect having a size larger than 500 μm due to a combination of defects grown separately. For this, by adopting a flange part extending outwardly from the side wall substantially parallel to the upper lid at the lower end of the side wall of the housing member, the gas flow is made to be single crystal by the flange part. It is possible to restrict the growth direction to a direction perpendicular to the growth direction, thereby suppressing the formation of dents, steps, and macro defects, and high-quality single crystals can be manufactured.

It is a cross-sectional schematic diagram which shows the single crystal manufacturing apparatus of 1st Embodiment which concerns on this invention. It is a cross-sectional schematic diagram of the crucible with which the single crystal manufacturing apparatus of 1st Embodiment which concerns on this invention is provided. FIG. 3 is a schematic diagram illustrating a configuration in which a cylindrical extension member is connected to a lower end portion of a side wall in the housing member illustrated in FIG. 2. It is an enlarged view of the upper part of the crucible shown in FIG. It is the enlarged view which showed the upper part of the crucible shown in FIG. 2 together with the seed crystal and the single crystal grown on it. It is a figure which shows typically the dent or level | step difference formed in the outer surface of a single crystal when a clearance gap is too large. It is an enlarged view of the upper part of the crucible with which the single crystal manufacturing apparatus of 2nd Embodiment which concerns on this invention is provided. FIG. 8 is a schematic diagram for explaining a method for increasing the length of the entire storage member in the storage member shown in FIG. 7, wherein (a) is a configuration before the increase, and (b) is a configuration after the increase. It is. It is the schematic diagram of the part of the outer surface of the silicon carbide single crystal (Example 1) obtained using the single crystal manufacturing apparatus of this invention. It is the schematic diagram of the part of the outer surface of the silicon carbide single crystal (Example 2) obtained using the single crystal manufacturing apparatus of this invention. It is a schematic diagram of the part of the outer surface of the silicon carbide single crystal obtained using the single crystal manufacturing apparatus of the comparative example. It is a figure which shows typically the polycrystal of silicon carbide formed between a guide member and the growth surface of a silicon carbide single crystal.

Hereinafter, a single crystal manufacturing apparatus, a housing member, and a method for manufacturing a silicon carbide single crystal according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. Although the present invention can be applied to vapor phase growth methods such as a sublimation method and a CVD method, a case where the sublimation method is used will be described as an example. The drawings referred to in the following description are for explaining the single crystal manufacturing apparatus, the housing member, and the manufacturing method of the single crystal of the present embodiment, and the sizes, thicknesses, dimensions, etc. of the respective parts shown in the drawings are actual. This may be different from the dimensional relationship of the single crystal manufacturing apparatus. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not necessarily limited to these, and can be appropriately changed and implemented without changing the gist thereof.
The housing member of the present invention will be described together with the following description of the single crystal manufacturing apparatus.
The following description will be made with a silicon carbide (SiC) single crystal in mind. However, the present invention is not limited to other single crystals that can be manufactured using a vapor deposition method (for example, gallium nitride (GaN) single crystal, aluminum nitride ( (AlN) single crystal etc.).

[Single Crystal Manufacturing Apparatus (First Embodiment)]
With reference to FIGS. 1-5, the structure of the single-crystal manufacturing apparatus to which the 1st Embodiment of this invention is applied is demonstrated. FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a single crystal manufacturing apparatus, FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a crucible provided in the single crystal manufacturing apparatus, and FIG. 3 accommodates a cylindrical extension member. FIG. 4 is a schematic view showing a configuration connected to the lower end of the side wall of the member, FIG. 4 is an enlarged view showing a part of the upper part of the crucible, and FIG. 5 shows the upper part of the crucible shown in FIG. It is the enlarged view shown together with the single crystal grown on it.

  The single crystal manufacturing apparatus to which the first embodiment of the present invention is applied is a single crystal manufacturing apparatus for manufacturing a single crystal by growing the single crystal S on the growth surface Wa of the seed crystal W arranged in the crucible 10. The crucible 10 is held on the upper lid 10a of the crucible 10 so as to be slidable in the vertical direction. A guide member 2 for guiding, and the guide member 2 includes a cylindrical portion 2a disposed so that at least the inner side surface 2aa of the upper end portion 2aa is substantially flush with the inner side surface 1ba of the housing member 1 in the vertical direction. And the upper end 2aa of the housing member 1 can be disposed so as to surround the growth surface side of the outer surface of the single crystal protruding downward from the lower end surface 1bba of the housing member 1, and the lower end surface 1bba of the side wall 1b of the housing member 1 And the upper end of the guide member 2 Gap between the 2aab are those that can be a 0.1~1.0mm at producing a single crystal. When the growth start surface comes out of the housing member before the growth starts, the growth surface side of the outer surface of the seed crystal is surrounded.

  A single crystal manufacturing apparatus 100 shown in FIG. 1 is schematically configured by placing a crucible 10 covered with a heat insulating material 102 inside a vacuum vessel 101 and a heating means 103 outside the vacuum vessel 101.

  The crucible 10 is surrounded by a heat insulating material 102 and is installed on a support rod 104 at the center inside the vacuum vessel 101. Holes 102 a and 102 b are formed in the heat insulating material 102 so that the lower surface and a part of the upper surface of the crucible 10 are exposed. The support rod 104 has a cylindrical shape, and the hole 104 a of the support rod 104 is aligned with the hole 102 a provided in the heat insulating material 102. The radiation thermometer 105 disposed under the vacuum vessel 101 can observe the temperature of the lower surface of the crucible 10 through the hole 104a of the support rod 104 and the hole 102a below the heat insulating material 102. Yes. Similarly, the temperature of the upper surface of the crucible 10 can be observed through another hole 102 b on the upper side of the heat insulating material 102 by another radiation thermometer 106 disposed on the vacuum vessel 101.

For the gas exchange inside the vacuum vessel 101, first, the air inside the vacuum vessel 101 is exhausted using a vacuum pump (not shown) connected to the discharge pipe 107, for example, 4 × 10 ⁻³ Pa or less. Reduce pressure. As the vacuum pump, for example, a turbo molecular pump or the like can be used. Thereafter, high-purity Ar gas is introduced into the vacuum vessel 101 from the introduction tube 108, and the inside of the vacuum vessel 101 (inside the furnace) is set to an environment of 9.3 × 10 ⁴ Pa in an Ar atmosphere, for example.

  The heating means 103 is, for example, a high-frequency heating coil, and can generate a high frequency by passing an electric current to heat the crucible 10 installed in the center of the vacuum vessel 101 to a temperature of 1900 ° C. or higher, for example. Thereby, the raw material powder P in the crucible 10 is heated, and sublimation gas is generated from the raw material powder P.

As shown in FIG. 2, the crucible 10 includes an upper lid 10a and a crucible body 10b.
The upper lid 10a can hold the accommodation member 1 that accommodates the seed crystal and the single crystal that grows on the growth surface in a vertically slidable manner, and has a through hole 10aa that has substantially the same diameter as the outer diameter of the accommodation member 1. It is formed at the center.
The crucible main body 10b includes a cylindrical side wall 10ba and a bottom 10bb.
A guide member 2 for guiding the source gas to the seed crystal side is fixed to the side wall 10ba of the crucible body 10b.

  The crucible 10 has a hollow portion 11 therein, and a lower part in the hollow portion 11 of the crucible 10 contains a sufficient amount of raw material powder P for crystal growth of a single crystal on the seed crystal. A space necessary for crystal growth of a single crystal is secured in the upper part. Therefore, the single crystal S can be grown on the growth surface Wa of the seed crystal W toward the bottom 10bb by the sublimation recrystallization method.

  As a material for the crucible 10, it is preferable to use a material that is stable at high temperatures and generates little impurity gas. For example, when producing a silicon carbide single crystal, it is preferable to use graphite (graphite), silicon carbide, or graphite (graphite) coated with silicon carbide or tantalum carbide (TaC).

The housing member 1 is a bottomed cylindrical member having a bottom portion 1a and a side wall 1b erected perpendicularly to the bottom portion, and is placed on the upper lid 10a of the crucible 10 so that the opened tip portion faces the raw material P. The formed through-hole 10aa is installed concentrically with the upper lid 10a.
The seed crystal W is fixed to the inner bottom surface 1aa which is the inner side of the bottom 1a of the housing member 1, and the housing member 1 can house a part of the single crystal grown on the seed crystal W together with the seed crystal W.

  As the material for the housing member 1, it is preferable to use a material that is stable at high temperatures and generates little impurity gas. For example, when producing a silicon carbide single crystal, it is preferable to use graphite (graphite), silicon carbide, or graphite (graphite) coated with silicon carbide or tantalum carbide (TaC).

As the sliding means (position adjusting means) (not shown) in the vertical direction of the housing member 1, for example, the one described in Patent Document 6 (while the single crystal is grown or the growth of the single crystal is temporarily interrupted) Thus, means for sliding the housing member continuously or stepwise along the growth direction of the single crystal can be used. More specifically, the slide means (position adjusting means) includes a frame portion that can move up and down in the growth direction of the single crystal along the outer periphery of the crucible, and a drive means that drives the frame portion in the vertical direction. The upper end of the frame part is fixed to the bottom part of the housing member via a connector.
Note that the vertical sliding of the housing member may be performed while growing a single crystal.

The housing member 1 can be connected to one or more cylindrical extension members at the lower end 1bb of the side wall 1b to increase the length in the crystal growth direction. FIG. 3 shows a configuration in which one cylindrical extension member 1c is connected to the lower end 1bb of the side wall 1b in the housing member 1 shown in FIG.
The timing for connecting the extension member is preferably performed when the length of the single crystal protruding downward from the lower end surface 1bba of the housing member 1 becomes 10 to 50 mm. When the length is 10 mm or less, the effect of the addition growth is small, and the addition of the addition member is difficult.
A method such as connection fitting of the housing member, screwing, adhesion with a carbon adhesive or the like can be used.

The guide member 2 is fixed to the cylindrical portion 2a arranged so that the inner side surface 2aaa of the upper end portion 2aa is substantially flush with the inner side surface 1ba of the housing member 1 and the side wall 10ba of the crucible body 10b. It consists of the support part 2b.
Here, “substantially flush” does not require strictly flush, and may deviate from flush within the range where the effects of the present invention are achieved. For example, the arrangement relationship may be shifted in parallel within a range of 0.3 mm or less from the same plane, or may be non-parallel within a range of 0.5 ° or less.

  The guide member 2 is arranged at a position where the upper end portion 2aa can surround the growth surface side Saa of the outer side surface Sa of the single crystal S protruding downward from the lower end surface 1bba of the housing member 1. Since the guide member 2 itself is fixed, the arrangement surrounding the growth surface side Saa of the outer surface Sa of the single crystal S is made by adjusting the position of the accommodating member 1 movable in the vertical direction.

During the growth of the single crystal, the gap d1 (see FIG. 5) between the lower end surface 1bba of the side wall 1b of the housing member 1 and the upper end surface 2aab of the cylindrical portion 2a of the guide member 2 is set to 0.1 to 1.0 mm. .
If this gap is 0.1 mm or more, the gas can sufficiently escape from this gap to the extent that polycrystal deposition on the inner surface of the guide member 2 can be sufficiently suppressed. Moreover, if it is 1.0 mm or less, the generation | occurrence | production of the dent or level | step difference of the outer surface of a single crystal and macro defect by gas escaping from a clearance gap can fully be suppressed. When a dent or a step is generated on the outer surface of the single crystal, sublimation occurs in that portion, which becomes a hollow defect, and sublimation / reprecipitation occurs in the defect, resulting in a macro defect.
It is technically difficult to completely prevent dents, steps, or macro defects, and it may not be a good idea to aim at complete prevention from a cost standpoint. It is often sufficient if a wide area can be used as a product. Therefore, in the present invention, the fact that dents or steps and macro defects generated on the outer surface of a single crystal can be sufficiently suppressed means that the dents or steps and macro defects can be reduced as compared with the case of the prior art. Further, as a guideline, it means that preferably 90% or more of the obtained single crystal can be used as a product, more preferably 95% or more can be used as a product. In addition, although the dent, step, or macro defect generated on the outer surface can be visually recognized, it may not be used as a product due to the internal defect formed due to the dent, step, or macro defect. The above-mentioned ratio is a ratio including such defects.

The gap d2 (see FIG. 5) between the outer surface Sa of the single crystal S and the inner surface 2aaa of the upper end 2aa of the guide member 2 surrounding the outer surface is preferably 0.1 to 1.5 mm. .
If the gap is 0.1 mm or more, the guide member can be installed without damaging it. Moreover, if this clearance gap is 1.5 mm or less, expansion can be suppressed and the possibility of cracking can be reduced.

As the material of the guide member 2, it is preferable to use a material that is stable at high temperatures and generates little impurity gas. For example, when producing a silicon carbide single crystal, it is preferable to use graphite (graphite), silicon carbide, or graphite (graphite) coated with silicon carbide or tantalum carbide (TaC).
When the guide member 2 is made of graphite (graphite) coated with tantalum carbide (TaC), it is effective to coat at least the surface facing the seed crystal side with tantalum carbide. The reason for coating with tantalum carbide (TaC) is that when the carbon of graphite is exposed, the raw material gas reacts with the carbon, and the carbon enters into the growing single crystal as quality deteriorates. This is to prevent this, and if only the surface facing the seed crystal side is coated with tantalum carbide, this deterioration in quality can be prevented.

According to the single crystal manufacturing apparatus of the present embodiment, since there is a moderately large gap between the lower end surface of the housing member 1 and the upper end surface of the guide member 2, gas can escape through this gap. As a result, the deposition of polycrystals on the inner surface of the guide member is suppressed, and the formation of dents or steps on the outer surface of the single crystal and macro defects due to the escape of gas from the gap.
FIG. 6 is a diagram schematically showing a dent or a step formed on the outer surface of the single crystal when the gap between the lower end surface of the housing member 1 and the upper end surface of the guide member 2 is too large. By having this gap, it is possible to suppress polycrystals from being displayed on the guide member. However, if the gap is too large, the outer surface of the single crystal has a depression or step that has a significant effect on the quality. Can be done. This dent or step will induce other defects.

[Method for Producing Single Crystal (First Embodiment)]
A single crystal manufacturing method using the single crystal manufacturing apparatus according to the first embodiment will be described.
First, the raw material P (for example, SiC powder) is filled in the crucible 10 and the seed crystal W is fixed to the inner bottom surface 1aa of the housing member 1.
Next, the lower end surface 1bba of the side wall 1b of the housing member 1 has a clearance of 0.1 to 1.0 mm between the upper end surface 2aab of the guide member 2 and the inner side surface 1ba is the upper end portion of the guide member 2. The position is adjusted so as to be substantially flush with the inner surface 2aaa of 2aa in the vertical direction.
Next, the raw material P is heated to grow a single crystal S on the growth surface Wa of the seed crystal W. When the single crystal S is grown and has a length that protrudes downward from the lower end surface 1bba of the side wall 1b of the housing member 1, a part of the growth surface side Saa of the outer surface Sa of the single crystal S is a guide. The member 2 is surrounded by the upper end 2aa.
Next, when the single crystal S has a length protruding from the lower end surface of the side wall of the housing member 1 to the lower side, for example, about 10 to 50 mm, the growth of the single crystal is temporarily interrupted, In order to extend the length of the housing member 1 in the crystal growth direction, an extension member is attached. At that time, the gap between the lower end surface of the extension member and the upper end surface 2aab of the guide member 2 is 0.1 to 1.0 mm, and the inner side surface thereof is substantially in the vertical direction with respect to the inner side surface of the upper end portion of the guide member. Adjust the position so that they are flush.
The connection of the extension member can be performed by fitting, screwing, bonding with a carbon adhesive, or the like. After the single crystal growth, the housing member may be removed once, and a new housing member may be reattached to perform growth.
Next, the growth of the single crystal is resumed.
If necessary, the raw material P may be added to the crucible 10 or replaced with a new raw material.
Connection of a new extension member and addition or exchange of the raw material P can be performed as many times as necessary.

[Single Crystal Manufacturing Apparatus (Second Embodiment)]
FIG. 7 is a schematic configuration diagram of a crucible provided in a single crystal manufacturing apparatus to which the second embodiment of the present invention is applied. The single crystal manufacturing apparatus to which the second embodiment is applied is the same as the single crystal manufacturing apparatus to which the first embodiment is applied except for the crucible.

The crucible of the second embodiment is different from the crucible of the first embodiment in that a crucible portion extending outwardly from the side wall to the crucible's upper cover is provided at the lower end of the side wall of the housing member. It is.
That is, as shown in FIG. 7, the housing member 21 provided in the crucible 20 is a bottomed cylindrical member having a bottom portion 21 a and a side wall 21 b standing upright with respect to the bottom portion. A flange portion 21c is provided extending outward from the side wall substantially parallel to the upper lid 20a.
It suffices if the lower surface of the buttock (raw material side surface) is substantially parallel to the upper lid.
Here, “substantially parallel” does not need to be strictly parallel, and may be deviated from parallel within a range in which the effect of the present invention is exerted, for example, non-parallel within a range of 0.5 ° or less. There may be.

The flange 21c preferably extends outward from the outer surface of the side wall of the housing member 21 by 4 to 10 mm.
When the extending length is less than 4 mm, a dent or a step is generated on the outer surface of the single crystal, and many macro defects starting from the dent may be generated. Moreover, when the extended length exceeds 10 mm, a polycrystal may be formed in the clearance gap between the lower end surface of an accommodating member and the upper end surface of a guide member, or a collar part.

  According to the single crystal manufacturing apparatus of the present embodiment, since the housing member 21 includes the jaw portion 21c at the lower end of the side wall, the flow of the gas exiting the gap can be restricted in the direction perpendicular to the growth direction of the single crystal. it can. Thereby, formation of the dent, level | step difference, and macro defect of the outer surface of the single crystal in the vicinity of the clearance gap can be suppressed. As a result, it is possible to manufacture a long single crystal with high quality without adding processing and removal of the enlarged growth portion.

  Also in the housing member provided in the crucible of the second embodiment, the same means as the housing member according to the first embodiment can be used as the vertical sliding means (position adjusting means).

Moreover, also about the housing member according to the second embodiment, the length in the crystal growth direction can be increased, similarly to the housing member according to the first embodiment. An example is shown in FIG.
In the example shown in FIG. 8, the side wall of the housing member is composed of a bottom side portion and a side portion having a flange portion, and before extending the length, a bottom side portion 21ba and a side portion 21bb having a flange portion are provided. In the accommodating member 21 (FIG. 8 (a)), the accommodating member 21 ′ in which the portion 21bb on the side having the collar portion is replaced with a long side wall 21bb ′ as shown in FIG. 8 (b). By doing so, the entire length of the housing member can be extended.
In the example shown in FIG. 8, the side wall of the housing member is composed of two parts, that is, a part on the bottom side and a part on the side having the collar part, and the length of the part on the side having the collar part is replaced with a longer one. Although the length of the entire storage member is increased, the side wall of the storage member is composed of three parts: a bottom part, a part having a flange part, and a connection part that connects these parts, and the connection part. The length of the entire storage member may be increased by exchanging the length of the storage member with a longer one. Even when there are two or more connecting portions, the entire length of the housing member may be increased by exchanging a part of the connecting portions with a longer one.

[Method for Producing Single Crystal (Second Embodiment)]
The single crystal manufacturing method using the single crystal manufacturing apparatus according to the second embodiment can also be performed in the same manner as when the single crystal manufacturing apparatus according to the first embodiment is used.

  Hereinafter, an embodiment in which a silicon carbide single crystal is manufactured using the single crystal manufacturing apparatus, the housing member, and the single crystal manufacturing method of the present invention will be described, but the present invention is not limited to this embodiment. .

Example 1
The single crystal manufacturing apparatus used in Example 1 has the configuration shown in FIG. The crucible was a cylindrical member made of a graphite substrate, had an inner diameter of 100 mm, and a height of 250 mm. Further, the length of the side wall of the housing member (the length of the inner surface) is 30 mm, the gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member is 0.25 mm, The length extending outward from the side wall of the housing member was 4 mm.
The growth of the silicon carbide single crystal was performed using the single crystal manufacturing apparatus having the configuration shown in FIG.
Silicon carbide raw material powder was housed in the lower part of the crucible, and a silicon carbide seed crystal having a diameter of 76 mm (3 inches φ) and a thickness of 0.8 mm was stuck in the housing member using a carbon adhesive.
Next, the crucible was heated to 2100 to 2400 ° C. in an inert atmosphere under reduced pressure of nitrogen (N ₂ ) and argon (Ar). At this time, the temperature on the silicon carbide raw material powder side was set 20 to 200 ° C. higher than the temperature on the silicon carbide seed crystal side, and a silicon carbide single crystal was deposited on the seed crystal using the temperature difference as a driving force. About 10 mm from the lower end surface of the side wall of the housing member, when the single crystal protrudes, it stops growing and is taken out once, the side wall (length of the inner surface) is reattached with a new housing member, and the growth continues. A silicon carbide single crystal having a thickness of 60 mm was obtained.

FIG. 9 is a schematic diagram of a portion of the outer surface of the obtained silicon carbide single crystal.
A dotted line indicated by a reference numeral 31 in the drawing indicates an added interface. Here, the addition interface is the growth start surface of the last crystal growth.
Although there is a region (step portion (reference numeral 32 in the figure)) having different outer diameters in a portion near the gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member, a wide region of the obtained single crystal There were no macro defects that could make it unusable as a product, and it was possible to grow high quality and long single crystals. The step (dent) of the step portion was 0.5 mm or less.

(Example 2)
In Example 2, the same single crystal production apparatus was used except that the single crystal production apparatus used in Example 1 was used and a crucible having no flange was used, and the growth conditions of the single crystal were the same.

FIG. 10 is a schematic diagram of a portion of the outer surface of the obtained silicon carbide single crystal.
A dotted line indicated by a reference numeral 31 in the drawing indicates an added interface. Moreover, the line shown with the code | symbol 33 shows a macro defect.
In Example 2, the step portion (reference numeral 32 in the figure) was larger than that in Example 1, and macro defects occurred on the outer surface, but the macro defect region did not further expand even if the growth continued. The step (dent) of the step portion was about 1 mm. Polycrystal was not produced.

  In both cases of Examples 1 and 2, no polycrystalline silicon carbide is formed between the guide member and the growth surface of the single crystal, and the portion of the portion that has grown larger than the diameter of the silicon carbide seed crystal is processed. Even without removal (ie, without processing), it was possible to add and grow. Moreover, Example 1 has a dent smaller than Example 2, and as a result, it can be understood that sublimation from the dent is suppressed and the occurrence of macro defects is suppressed.

(Comparative example)
In the comparative example, the single crystal manufacturing apparatus used in Example 1 and a crucible having no flange and having a gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member of 1.5 mm. Except for the points used, the same single crystal production apparatus was used, and the growth conditions of the single crystal were the same.

FIG. 11 is a schematic diagram of a portion of the outer surface of the obtained silicon carbide single crystal.
A dotted line indicated by a reference numeral 31 in the drawing indicates an added interface. Moreover, the line shown with the code | symbol 33 shows a macro defect.
In the comparative example, a step portion (reference numeral 32 in the drawing) that is deeper than that of the second embodiment is formed on the outer surface, and larger macro defects are generated than in the second embodiment. The area has expanded. The step (dent) of the step shown in FIG. 11 was about 2 mm. In addition to the macro defects shown in FIG. 11, many macro defects occurred on the outer surface.

  The single crystal production apparatus, the single crystal production apparatus housing member and the single crystal production method of the present invention can be used for producing a high-quality and long single crystal.

1, 21 Housing member 1a Bottom portion 1b Side wall 1bb Lower end portion 1bba Lower end surface 1c Additional member 2 Guide member 2a Cylindrical portion 2aa Upper end portion 2aaa Inner side surface 2aab Upper end surface 2b Support portion 10, 20 Crucible 10a Upper lid 10b Crucible body 100 Single crystal production Device W Seed crystal S Single crystal

Claims (6)

A single crystal production apparatus for producing a single crystal by growing a single crystal on a growth surface of a seed crystal arranged in a crucible,
A bottomed cylindrical accommodating member that is slidably held in the upper and lower directions on the upper lid of the crucible and can accommodate a seed crystal;
A guide member fixed to the side wall of the crucible and guiding the source gas to the seed crystal side,
The guide member has a cylindrical portion that is arranged so that at least an inner surface of an upper end portion thereof is substantially flush with an inner surface of the accommodating member in the vertical direction, and the upper end portion is a lower end surface of the accommodating member. Can be arranged so as to surround the growth surface side of the outer surface of the single crystal protruding downward from
The single crystal manufacturing apparatus characterized in that the gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member can be 0.1 to 1.0 mm at the time of manufacturing the single crystal.   2. The single crystal manufacturing apparatus according to claim 1, further comprising a flange portion extending outwardly from the side wall of the housing member substantially in parallel to the upper lid at a lower end of the side wall of the housing member.   The single crystal manufacturing apparatus according to claim 2, wherein the flange portion extends outward from the side wall of the housing member by 4 to 10 mm.   The clearance gap between the outer surface of the said single crystal and the inner surface of the upper end part of the said guide member surrounding the outer surface is 0.1-1.5 mm, The any one of Claims 1-3 characterized by the above-mentioned. The single-crystal manufacturing apparatus as described in any one. A method for producing a single crystal by growing a single crystal on a growth surface of a seed crystal disposed in a crucible,
A bottomed cylindrical housing member that contains a seed crystal so as to be slidable in the vertical direction on the upper lid of the crucible;
A guide member that is fixed to the side wall of the crucible and guides the source gas to the seed crystal side, and is arranged so that at least the inner surface of the upper end portion thereof is substantially flush with the inner surface of the housing member in the vertical direction. Using a guide member having a cylindrical portion,
The gap between the lower end surface of the side wall of the housing member and the upper end surface of the guide member is 0.1 to 1.0 mm,
A method for producing a single crystal, comprising: growing the single crystal in a state where the guide member is arranged so that an upper end portion of the guide member surrounds a growth surface side of the outer surface of the single crystal. 6. The single crystal production according to claim 5 , wherein the housing member is provided with a flange portion extending outwardly from the side wall substantially parallel to the upper lid at the lower end of the side wall. Method.

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