JPS5855120B2 - Vapor phase epitaxial growth method of magnesia spinel - Google Patents

Description

Detailed Description of the Invention The present invention provides single crystal magnesia spinel (M
Regarding the method of vapor phase epitaxial growth of gO-A7203), more specifically, during vapor phase growth, between the magnesium source region and the growth region, the vapor of magnesium chloride (MgC12) generated in the source region forms on the inner wall of the reaction tube. MgO prevents Mg from being deposited on the liner tube surface and increases the utilization efficiency of Mg (J!2).
-Relates to a method for vapor phase epitaxial growth of Al2O3.

Conventional Mg0-Al, which the inventors have already proposed, 20
In the second vapor phase epitaxial growth method, growth was performed using an apparatus as shown in FIG.

That is, in the source region A upstream with respect to the flow of gas in the reaction tube 1, there is a first source chamber 3a whose one end is connected to the gas introduction tube 2a and whose other end is open into the reaction tube 1;
It has a second source chamber 3b whose one end is connected to the gas introduction tube 2b and the other end opens into the reaction tube, and a gas introduction tube 2c which opens directly into the reaction tube 1, and has a downstream region of the gas inside the reaction tube 1. A carbon heating element 4 is disposed in the growth region B, and sometimes a liner tube 5 is provided between the heating element 4 and the reaction tube 1, and resistance heating is provided on the outer periphery of the reaction tube in the source region A. A high-frequency heating coil 1 is provided on the outer periphery of the reaction tube in the growth region B.

In the figure, 8 indicates a reaction tube camp, and 9 indicates a gas discharge pipe.

The conventional vapor phase epitaxial growth method for Mg0-AA203 uses an apparatus having the structure described above, in which magnesium chloride (MgC12) is placed as a magnesium (Mg) source 10 in the first source chamber 3a, and magnesium chloride (MgC12) is placed in the first source chamber 3a. An aluminum (Al) source 11 is provided in the chamber 3b.
The first source chamber 3 is placed with metal Al as a
The Mg source 10 is heated to about 900 to 950 ('C) by the resistance heater 6a while hydrogen (H2) is introduced into the second source checker/par 3b. Without introducing the mixed gas, heat the A7 source 11 to about 550 ('C) using a resistance heater ``b''.
A mixed gas of carbon dioxide (CO2) and H2 is introduced from the gas introduction pipe 2c, while a silicon (Sl) substrate 12 to be grown is placed on the carbon heating body 4, and a high frequency heating coil 7
The temperature of the Si substrate 12 is raised to approximately 950 (° C.).

Then, MgC132 vapor generated from the Mg source 10 and aluminum chloride (
AlC13) CO introduced from steam and gas introduction pipe 2c
In this method, a single crystal of MgO--Al2O3 was grown on the Si substrate 12 by reacting the MgO--Al2O3 with MgO--Al2O3 in the growth region B.

However, in such a conventional method, since a heater is not provided in region C between source region A and growth region B, the temperature profile inside the reaction tube becomes as shown in FIG.
Mg source region at temperature 900 ('C) and temperature 950
Approximately 600 [℃] in area C between growth area B of ('C)
MgCl2 with low vapor pressure in the region C is liquefied or solidified to create a valley E with a temperature of about MgC on the inner wall of the tube 1 or the surface of the liner tube 5
A large amount of 1!2 precipitates 13 occur, and the amount of MgCl2 sent into the growth region B becomes insufficient.

For that purpose, MgO・A I! on the Si substrate 12! 20
The growth of 3 becomes unstable, and depending on the location on the substrate surface, Mg
There are cases where O--Al2O3 is not formed or, in some cases, it is not possible to grow MgO--Al2O3 on the substrate at full heat, resulting in a problem that only a low growth yield of about 50% can be obtained.

Therefore, in order to prevent the temperature gap from forming between the Mg source and the growth region as described above, attempts have been made to bring the growth region closer to the Mg source, but in this case, heating the Si substrate is Since the influence of the high frequency applied to the Mg source region affected the Mg source region, the temperature of MgCl2, which is the Mg source, became unstable, and desired results could not be obtained.

In view of the above-mentioned opening points of the present invention, Mg source and Mg
The MgCl2 vapor generated by the Mg source between the O-Al2O3 growth region is not liquefied or solidified and precipitated, and therefore MgO-Al2O can be grown with a high yield.
3. A method capable of performing vapor phase epitaxial growth;
and Mg0-, which further improves the growth efficiency using a catalyst.
Al! 203 vapor phase epitaxial growth method is provided.

That is, the present invention reduces the amount of wetting in the @ region between the source region and the growth region when growing a magnesia spinel (MgO-A1203) single crystal in the vapor phase using a horizontal vapor phase epitaxial growth method. A vapor phase epitaxial growth method for magnesia spinel (MgO-A1203) characterized by growing at a temperature higher than Magnesium oxide (MgO) and alumina (A12) produced by the reaction of magnesium chloride and aluminum chloride with carbon dioxide as reaction catalysts are placed inside the reaction tube in the
The present invention relates to a method for vapor phase epitaxial growth of magnesia spinel (MgO-A1203), which is characterized in that growth is performed by providing an adhesion layer consisting of 03).

The present invention will be explained in detail below with reference to a cross-sectional structural diagram of a vapor phase growth apparatus used in an embodiment shown in FIG. 3 and a temperature profile diagram inside a reaction tube in an embodiment shown in FIG.

For example, in the vapor phase growth apparatus used in one embodiment of the present invention, as shown in FIG. A second source chamber 3b1 and a gas introduction pipe 2c connected to the gas introduction pipe 2b are provided, and a substrate pedestal 14 made of quartz or the like is provided in the growth region, and sometimes reacts with the substrate pedestal 14. Liner tube 5 between tube 1
Resistance heaters 6a and 6b are provided on the outer periphery of the reaction tube in source region A, resistance heater 6c is provided on the outer periphery of the reaction tube in growth region B, and resistance heaters 6c are provided on the outer periphery of the reaction tube in growth region B. It has a structure in which a resistance heater 6d is disposed around the outer circumference of the tube.

In the figure, 8 indicates a reaction tube cap, and 9 indicates a gas discharge tube.

To explain one embodiment of the method of the present invention using the vapor phase growth apparatus having the above structure, first, MgC placed in a boat as the Mg source 10 is placed in the source chamber 3a.
H2 is introduced onto the Mg source 10 from the gas introduction pipe 2a at a flow rate of, for example, 5 [L/min], and multiple sources placed in a boat are placed in the source chamber 3b as the A7 source 11. Gas introduction pipe 2b is placed on the thin metal Ad rod of
For example, a mixed gas of hydrochloric acid (HC7) at a flow rate of 5 (cc/min) and H2 at a flow rate of gas 5CL/min is introduced from the gas introduction pipe 2c, and CO2 at a flow rate of 100 (cc/min) is introduced from the gas introduction pipe 2c.
A mixed gas of H2 and H2 at a flow rate of 20 [L/min] is introduced.

Then, the resistance heater 6a heats the Mg source 10, e.g.
Heat to 50 (℃) to generate MgC1!2 vapor,
In addition, the A7 source 11 is heated to a temperature of, for example, 550 mm by the resistance heater 6b.
[°C] to generate AlCl13 vapor, these Mg C1!2 vapors and AlCl3 vapors are mixed with CO2 introduced from the gas introduction pipe 2c, and together with the carrier gas B2, the resistance heater 6d is heated. It is fed into the growth region B through the region C between the Mg source 10 and the growth region B, which is heated and maintained at a higher temperature than the Mg source 10 by the above-mentioned method.

In the growth region B, which is heated to 950 (°C) by the resistance heater 6C, 1 consisting of MgO and Al2O3, which is produced by the reaction of MgC72 and AIICIJ3 with CO2, as shown in the reaction formula below. 5-2 [μ
magnesia spinel [MgO-Al2] about the same thickness as a door]
A single crystal layer of O3] is grown on a growth target Si substrate 12 made of single crystal silicon placed on a substrate pedestal 14 disposed in the region.

An example of the temperature profile inside the reaction tube in the above embodiment is as shown in FIG.
50 ('C), the temperature of the Mg source region is 750 [°C]
, the temperature of the growth region B is 950 [°C], and the region C between the Mg source region and the growth region B is between the temperature of the Mg source region of 750 [°C] and the temperature of the growth region B of 950 [°C]. It has a temperature profile that connects the two with a plus (+) temperature gradient.

By performing the vapor phase growth of MgO/Al2O3 with the above-mentioned profile using the method of the present invention, MgC, which is extremely prone to forming precipitates due to its extremely low vapor pressure, can be grown.
Since the region C between the Mg source region and the growth region B is kept at a higher temperature than the Mg source region, the precipitation of MgCl2 in the region C is eliminated.
The MgCl2 vapor generated in the source region is almost completely supplied to the growth region B, and therefore the temperature of the Mg source is 150 [°C] lower than the conventional temperature750
Although it is set to ('C), high growth efficiency can be obtained.

Furthermore, in the growth apparatus of this embodiment shown in FIG. 3, since the reaction tube 1 and the liner tube 5 are heated by the resistance heaters 6c and 6d, the inner wall of the reaction tube 1 in the growth region B and the Mg source region are heated. The temperature of the inner wall of the reaction tube 1 in the region C between the growth region B and the inner wall of the liner tube 5 disposed in the reaction tube 1 approaches the growth temperature, and the temperature of the inner wall of the reaction tube 1 in the region B exposed to the reaction gas approaches the growth temperature. In the vicinity of the inner wall, the inner wall of the reaction tube 1 in region C, and the inner wall of the liner tube 5, a reaction similar to that on the silicon substrate 12 occurs, and reaction products are deposited on the surfaces of the respective inner walls.

However, unlike on the silicon substrate 12, the growth temperature, gas concentration, gas flow rate, etc. are not balanced in the areas B1 and C on the inner wall of the reaction tube 1 and on the inner wall of the liner tube 5, so that they are of the same quality as on the silicon substrate 12. Mg0472
037%, a mixture of MgO and A4.03 is produced, and polycrystals are produced instead of single crystals.

When growth is performed on the silicon substrate 12 with this product deposited, MgC
Since the reaction of 12+H2→Mg+2HC7 is promoted and stabilized, the growth properties of MgO.Al2O3 are improved and the growth is stable.

Here, the product that becomes the catalyst is transferred to the area B1 of the inner wall of the reaction tube 1.
The deposition step of actively depositing Mg on the region C or the inner wall of the liner tube 5 is performed by applying Mg onto the silicon substrate 12, for example, in the same manner as on a normal silicon substrate 12.
This can be done by performing it before growing the O-Al2O3 layer.

However, with this method, it may not be possible to uniformly deposit the product serving as a catalyst over the entire inner wall of the liner tube 5, and if a large number of silicon substrates 12 are to be grown at the same time, each substrate Uniform Mg
It may not be possible to grow O-Al2O3.

In such a case, such inconvenience can be prevented by switching the front and back of the liner tube 5 and depositing the product that will become the catalyst.

Furthermore, the method of depositing the product to serve as a catalyst on the liner tube 5 does not necessarily have to be carried out in the reaction tube 1 that processes the substrate, but can be performed in advance by depositing the product on the liner tube 5 in a separate device. Even if the liner tube 5 is then placed in the reaction tube 1 and growth is performed on the treated substrate, the effect remains the same.

S
A single crystal of i is grown, and its electron mobility - (μ
MgO.Al2 grown by the method of the present invention shows a value of around 300Ccr/12//v-8ec].
It can be seen that the O3 layer has a high quality single crystal structure.

In the above embodiments, the present invention has been explained with reference to an example in which a magnesia spinel single crystal layer is grown in a vapor phase on a single crystal Si substrate. It can also be applied to the vapor phase growth of magnesia spinel single crystals on compound semiconductor substrates.

As explained above, according to the method of the present invention, the family head efficiency of a magnesia spinel single crystal can be significantly improved and stabilized, and a high quality magnesia spinel single crystal layer can be obtained.

Therefore, it is possible to simultaneously grow high-quality magnesia spinel single crystal layers on multiple semiconductor substrates with a high yield.
It is possible to improve the characteristics of a semiconductor device having an O8 structure and to reduce manufacturing costs.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional structural diagram of a vapor phase growth apparatus used in the conventional vapor phase epitaxial growth method of magnesia spinel, and Figure 2 is a diagram of the temperature profile inside the reaction tube in the conventional method.
FIG. 3 is a cross-sectional structural diagram of a vapor phase growth apparatus used in the vapor phase epitaxial growth method of magnesia spinel of the present invention;
The figure is a temperature profile diagram inside a reaction tube in the method of the present invention. In the figure, 1 is a reaction tube, 2a12b+2c is a gas introduction tube, 3a and 3b are source chambers, 4 is a carbon heating element, 5 is a liner tube, 6a, 6b+6c, and 6d are resistance heaters, and 7 is a high-frequency heating coil. , 8 is the reaction tube cap, 9 is the gas exhaust pipe, 10 is the magnesium source, 1
1 is an aluminum source, 12 is a silicon substrate, 13
is the precipitation of MgC112, 14 is the substrate stage, A is the source region, B is the growth region, C is the region between the source region and the growth region, D is the magnesium source region, E is the temperature valley, F
is the aluminum source region.

Claims (1)

[Claims] 1. When vapor phase growing a magnesia spinel (MgO-A1203) single crystal using a horizontal vapor phase epitaxial growth method, the temperature of the region between the source region and the growth region is controlled to be at least as low as that of the magnesium source. A vapor phase epitaxial growth method for magnesia spinel, which is characterized by growing at a higher temperature. 2 Magnesium oxide (MgO) and alumina (MgO), which are produced by the reaction of magnesium chloride and aluminum chloride with carbon dioxide as reaction catalysts, are placed in the region between the source region and the growth region and inside the reaction tube in the growth region. k
! 2. The method for vapor phase epitaxial growth of magnesia spinel according to claim 1, characterized in that the growth is carried out by providing an adhesion layer consisting of 1203).