JPS62109313A - Vapor growth method - Google Patents

Abstract

PURPOSE:To obtain a crystal having a uniform and abrupt boundary by placing a substrate horizontally on a substrate holder provided rotatably at a vertical shaft as a center, and supplying stock gas on the substrate from obliquely above. CONSTITUTION:A substrate 2 is horizontally placed in a substrate holder 1, stock gas or stock gas diluted by carrier gas is fed from a stock gas inlet 4 to a reaction chamber 3 at an angle inclined at 45-90 deg. from a normal to the substrate 2. A stock gas stream 5 passes in a laminar state on the substrate 2 similarly to a lateral type. Since the substrate 2 is made rotatable by rotating a vertical shaft 22 similarly to a vertical type, a crystal which has both excel lent uniformity and boundary sharpness is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vapor phase growth method for epitaxially growing a crystal on a substrate by introducing a source gas into a reaction chamber.

[Conventional technology]

The vapor phase growth method is a crystal growth method with excellent mass productivity and uniformity, but it can be divided into vertical and horizontal types depending on the flow direction of the raw material gas introduced into the substrate.

FIG. 3 is a schematic diagram showing a conventional vertical type vapor phase growth method, in which a substrate 13 is placed on a substrate holder 12 provided in a reaction chamber 14, and a source gas is introduced from a source gas inlet 15. The direction is vertically downward to the substrate 13 (the raw material gas flow 1 is shown in the figure).
6). Further, the substrate holder 12 rotates about a vertical axis 21, thereby also rotating the substrate 13 to ensure uniformity of the crystals on the surface of the substrate 13.

FIG. 4 is a schematic diagram showing a conventional horizontal vapor phase growth method, in which a substrate 17 is placed on a substrate holder 1 provided in a reaction chamber 18.
6, and the raw material gas is introduced from the raw material gas inlet 19 sideways toward the substrate 17 (the raw material gas flow 2 is shown in the figure).
0). In the horizontal type, the substrate 17 can be tilted so that the source gas passes over the substrate 17 while maintaining a laminar flow state, so the composition of the source gas can be switched smoothly, and there is no steep interface on the surface of the substrate 17. It is possible to obtain crystals with .

[Problem that the invention seeks to solve]

Among the conventional vapor phase growth methods described above, in the vertical type method shown in FIG. 3, the flow of the source gas is disturbed by the substrate 13 and the substrate holder 12, making it impossible to smoothly switch the source gas composition and causing a steep interface. It has the disadvantage that it is difficult to obtain and is easily affected by convection due to the heated substrate 13 and substrate holder 12. On the other hand, in the horizontal type shown in FIG. 4, it is difficult to introduce a rotation mechanism to rotate the substrate 17 so that the substrate 17 does not slip off the substrate holder 16.
Since the substrate 17 cannot be rotated, it is difficult to ensure uniformity of the crystal.

An object of the present invention is to provide a vapor phase growth method that makes use of the advantages of both the vertical method and the horizontal method to obtain crystals with uniform and steep interfaces.

[Means for solving problems]

The vapor phase growth method of the present invention is a vapor phase growth method in which a raw material gas diluted with a carrier gas is introduced into a reaction chamber to epitaxially grow a crystal on a substrate. The substrate is placed horizontally on a provided substrate holder, and the raw material gas is introduced into the reaction chamber in a direction inclined by 45° to 90° from the vertical direction.

In the vapor phase growth method of the present invention, the raw material gas diluted with a carrier gas may be introduced into the reaction chamber surrounded by a buffer gas that has a higher viscosity than the carrier gas and does not participate in crystal growth. .

〔Example〕

Hereinafter, the vapor phase growth method of the present invention will be explained with reference to illustrated examples.

FIG. 1 shows an embodiment of the vapor phase growth method of the present invention, in which a substrate 2 is placed horizontally on a substrate holder 1, and a raw material gas or a raw material gas diluted with a carrier gas is introduced into a reaction chamber 3. 45° to 90° from the normal line from the mouth 4 to the substrate 2
Introduced at an oblique angle. The raw material gas flow 5 passes over the substrate 2 in a laminar flow state as in the horizontal method. In addition, the substrate 2 is mounted on a vertical axis 22 with the substrate holder 1 in the same way as in the vertical type system.
Since it can be rotated by rotating, a crystal with excellent both uniformity and interface steepness can be obtained.

That is, in the embodiment shown in FIG. 1, since the substrate holder 1 places the substrate 2 horizontally, a mechanism for rotating the substrate 2 can be introduced, and the uniformity of the crystal can be ensured. Furthermore, since the raw material gas is introduced from a direction inclined from 456 to 90'' from the vertical direction, the raw material gas passes over the surface of the substrate 2 in a laminar flow state, which allows for a sharp change in gas composition and avoids sharp interfaces. It is possible to obtain crystals with

FIG. 2 shows another embodiment of the vapor phase growth method of the present invention, which includes a substrate holder 6, a substrate 71, a reaction chamber 8. The raw material gas inlet 9 is connected to the substrate holder 1 shown in FIG. Substrate 21 reaction chamber 3. Although it is similar to the raw material gas inlet 4, the first step is to flow a gas that has a higher viscosity than the carrier gas that dilutes the raw material gas and does not participate in crystal growth (hereinafter referred to as buffer gas) in a shape that surrounds the raw material gas. This is different from the embodiment shown in FIG.

Since the buffer gas introduced from the buffer gas inlet 10 provided to surround the raw material gas inlet 9 has a higher viscosity than the carrier gas, mixing of the carrier gas and the buffer gas occurs. The buffer gas flow 23 has the function of shaping the gas flow and maintaining a laminar flow state (buffer gas flow 23 is shown in the figure).

Therefore, the switching of source gases is performed more smoothly than in the embodiment shown in FIG. 1, and a crystal with a steep interface can be obtained.

In other words, in the embodiment shown in FIG. 2, the carrier gas and buffer gas, which have different viscosities, are difficult to mix with each other, so the buffer gas can shape the raw material gas and guide it to the substrate 7. suppressed,
The source gas can be made to pass over the substrate 7 while maintaining a laminar flow state. Therefore, the gas composition changes more sharply, and crystals with steep interfaces can be obtained with good reproducibility.

〔Effect of the invention〕

As explained above, the vapor phase growth method of the present invention has the advantages of both the vertical method and the horizontal method, and has the effect of being able to obtain crystals with uniform and steep interfaces. In particular, the present invention has the effect of obtaining a good interface in the formation of crystals for FETs, laser diodes, etc.

[Brief explanation of drawings]

1 and 2 are schematic diagrams of one embodiment of the present invention and another embodiment, FIG. 3 is a schematic diagram showing a conventional vertical type vapor phase growth method, and FIG. 4 is a schematic diagram of a conventional vertical type vapor phase growth method. FIG. 1 is a schematic diagram showing a conventional horizontal type vapor phase growth method. 1.6,12.16...Substrate holder, 2.7゜13
．． 17...Substrate, 3,8,14.18...Reaction chamber,
4.9, 15.19... Raw material gas inlet, 5, 11° 16.20... Raw material gas flow, 10... Buffer gas inlet. Mayuzumi 2 Father

Claims (2)

[Claims] (1) In a vapor phase growth method in which a raw material gas diluted with a carrier gas is introduced into a reaction chamber to epitaxially grow a crystal on a substrate, a substrate holder that is rotatable around a vertical axis and provided in the reaction chamber is used. A vapor phase growth method characterized in that the substrate is placed horizontally on the substrate and the raw material gas is introduced into the reaction chamber in a direction inclined by 45° to 90° from the vertical direction. (2) Vapor phase growth according to claim 1, wherein the raw material gas diluted with a carrier gas is introduced into the reaction chamber surrounded by a buffer gas that has a higher viscosity than the carrier gas and does not participate in crystal growth. Method.