JPS61189623A - Vapor growth equipment - Google Patents

Abstract

PURPOSE:To control more uniformly the temperature distribution in a region of reaction system of a vapor growth equipment, by providing a heating means also within the reaction system in addition to the outside of the reaction system. CONSTITUTION:In an epitaxial growth region, a growing substrate 9 carried on a wafer holder 8' is disposed within a liner tube 7 and heated by an external heating means, resistance furnace. A secondary heater 12 is incorporated within the holder 8'. By changing the shape and the exothermic distribution of this secondary heater 12 according to a temperature distribution that the growing unit inherently has, to growing conditions, and especially to a flow rate of a material gas, the temperature distribution is compensated and uniformized. This heater 12 is connected to a temperature control unit through an electrode taking-out orifice 13.

Description

[Detailed Description of the Invention] [Summary] In addition to the conventional heating device outside the reaction system in a vapor phase growth apparatus, a heating device is additionally provided inside the reaction system to control the temperature distribution inside the reaction system. shall be.

[Industrial application field]

The present invention relates to a vapor phase growth apparatus, and more particularly to a vapor phase growth apparatus that maintains a uniform temperature distribution in a growth region and a material gas generation region within the vapor phase growth apparatus.

[Conventional technology]

FIG. 2 is a schematic diagram of a conventionally used horizontal vapor phase epitaxial growth apparatus.

The vapor phase epitaxial growth of, for example, magnesia spinel (hereinafter referred to as spinel) will be explained below.

In the upper stage of the source chamber 2 arranged inside the reaction tube 1,
A source port 3 containing magnesium chloride (MgC1z) is mounted. This is heated using the resistance heating furnace 6b to generate 11gcβ2 gas, and the gas introduction pipe 5a
It is transported onto the growth substrate 9 by a gear gas introduced from the substrate. On the other hand, a source port 4 containing aluminum is placed in the lower stage of the source chamber 2, and is heated using a resistance heating furnace 6c. At the same time, hydrogen chloride (HCj2) gas introduced from the gas inlet 5b is reacted with aluminum to cause aluminum chloride (AlCl!
3) A gas is generated and transported onto the growth substrate 9 by a carrier gas introduced simultaneously with the HC1 gas.

Further, carbon dioxide gas (Co□) is introduced from the gas inlet 5c together with the carrier gas, and is also transported onto the growth substrate 9.

In the epitaxial growth region, a growth substrate 9 placed on a wafer holder 8 is disposed in a liner tube 7 and heated by a resistance heating furnace 6a.

On the growth substrate 9, the above MgCj! z, AICJ
: + etc. cause a reaction based on the following reaction formula, and spinel single crystal (MgO-A
．． 1) Grow.

MgCj'z + 2ANCf3 + 4H2+ 4C
Ot→MgO・Aji! zo:++811C1+
4CO [Problem to be Solved by the Invention] FIG. 4A shows the thickness distribution of the spinel film grown in this growth apparatus. This distribution is caused by the temperature distribution in the growth region, and the state of this temperature distribution is shown in FIG. As shown in FIG. 3, the temperature distribution on the wall of the reaction tube is constant as shown by the broken line, but the temperature distribution near the center of the reaction tube is as shown by the solid line. Note that FIG. 4B shows an enlarged view of the temperature distribution in the growth region of FIG. 3.

The above temperature distribution is mainly due to the cooling effect of the growth material gas flow and the cooling effect of convection from the exhaust side of the reaction tube.

To avoid this phenomenon, there is a method of increasing the length of the growth region and using a portion with a small temperature distribution, but increasing the length of the reaction tube causes the problem of increasing the size of the equipment and increasing cost. , a reaction occurs before the material gas reaches the growth substrate, resulting in the disadvantage that no growth occurs on the growth substrate. Another possibility is to move the growth substrate closer to the wall of the reaction tube, but this method is considered impossible in vapor phase growth equipment, especially horizontal equipment, due to problems with the shape of the reaction tube and growth substrate, and constraints imposed by the growth conditions. It will be done.

[Means for solving problems]

According to the present invention, the above-mentioned problems are solved by a vapor phase growth apparatus characterized in that a heating device is provided both outside and inside the reaction system of the vapor phase growth apparatus.

[For production]

That is, in the present invention, since a heating device is provided not only outside the reaction system of the vapor phase growth apparatus but also inside the reaction system, the temperature distribution in the reaction system region can be controlled more uniformly.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the apparatus according to the present invention, and is an enlarged view of the growth region of FIG. 2 showing a conventional example.

Conventionally, a processed quartz plate has been used as a wafer holder, but the present invention improves this wafer holder and incorporates a heater 12 for auxiliary heating inside the holder. This heater 12 compensates for and makes the temperature distribution uniform by changing its shape and heat generation distribution depending on the temperature distribution and growth conditions inherent in the growth apparatus, especially the flow rate of the material gas. In addition, this Q heater has electrode outlet 1.
3 is connected to a temperature control device (not shown).

In the above embodiment, an auxiliary heater is installed inside the wafer holder, but a similar auxiliary heater may be installed at the bottom of the wafer holder 8 in FIG. It is also possible to incorporate it into the liner tube 7.

In the previous section, we described a method to make the temperature distribution uniform in the growth region, but as is clear from Figure 3, MgCj2z
The temperature distribution is also non-uniform in the generation region and the AlCl3 generation region. Therefore, depending on the growth conditions, the concentration of the generated gas may not be controllable. Even in cases like this,
By installing an auxiliary heater similar to that in the previous section in the source port 3 or 4, the above-mentioned inconvenience can be avoided.

In the embodiment, a vapor phase growth apparatus for magnesia spinel was described, but the present invention can also be applied to other vapor phase growth methods using a similar apparatus.

〔Effect of the invention〕

As explained above, according to the present invention, a comparatively inexpensive small-capacity temperature control device and heater can be used without increasing the size of the vapor phase growth apparatus or using an expensive and complicated temperature control device. By adding this to the growth apparatus, the temperature distribution within the growth apparatus can be made uniform.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the apparatus according to the present invention, and is an enlarged portion of the growth region shown in FIG. 2, and FIG. 2 is a schematic diagram of a conventional horizontal vapor phase epitaxial growth apparatus. Figure 3 shows the temperature distribution during the reaction in the conventional apparatus, Figure 4A shows the film thickness distribution of the magnesia spinel film grown with the conventional apparatus, and Figure 4B shows the temperature distribution at the position corresponding to Figure 4A. be. 1... Reaction tube, 2... Source chamber, 3.
4... Source port, 5a, 5b, 5cm gas inlet, 6a, 6b,
6c:...resistance heating furnace, 7...liner tube,
8.8'... Wafer holder, 9... Growth substrate,
10...Camping, +1...Exhaust port, 1
2... Heater, 13... Electrode outlet.

Claims (1)

[Claims] 1. A vapor phase growth apparatus characterized in that a heating device is provided both outside and inside the reaction system of the vapor phase growth apparatus.