JPS59169999A - Gaseous phase growth of epitaxial growth - Google Patents

Abstract

PURPOSE:In subjecting crystal of semiconductor on a substrate of single crystal by vapor phase growth, making thickness of a semconductor layer of vapor phase epitaxial growth uniform in the whole surface, and to prevent autodoping from a susceptor, by putting a crystal plate between the susceptor and the substrate of single crystal. CONSTITUTION:The susceptor 2 is put in the upright reaction pipe 1, and the crystal plate 4 of GaAs is put between it and the substrate 3 of GaAs single crystal on it. In this state a semiconductor material in a gaseous phase is fed to them in the A direction and subjected to gaseous phase epitaxial growth at 700 deg.C for 1hr. The formed semiconductor has no thick ends as the conventional method, shows uniform thickness and flat state, and it will not receive autodoping from the susceptor 2, so it has no deterioration in electrical and optical characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for vapor phase growth of an epitaxial layer in which a semiconductor crystal material is transported in a vapor phase and epitaxially grown on a single crystal substrate.

Conventional Structure and Its Problems A semiconductor epitaxial layer produced using a vapor phase growth method is important in the production of semiconductor lasers and EFTs. For example, the former is optical communication, optical information processing, DAI)
The latter is used in a wide range of applications as a light source for , VD, laser printers, etc., and as a high-speed formation circuit component for microwaves and high frequencies.

Conventionally, such a semiconductor epitaxial layer has been produced by a vapor phase growth method using an apparatus as shown in FIG. That is, inside the reaction '1nn), the single crystal substrate (3) is placed directly on the susceptor (2), and the arrow (c)
As shown in , the semiconductor crystal material is heated in the gas phase in a reaction tube +1)
A desired crystal layer is epitaxially grown on the single crystal substrate (3). However, conventional methods using such devices have the following drawbacks.

(2) The crystal layer formed on the single crystal board (3) is thicker at the 11th side than at other parts.

(2) The crystal layer formed on the single crystal substrate (3) receives autodoping from the susceptor (2).

The above-mentioned drawback (1) is connected to the problem that the epitaxial layer in the peripheral area of the cut crystal substrate (3) cannot be used for device fabrication. On the other hand, the above drawback (2) leads to the problem of deteriorating the εd mechanical and optical characteristics of the formed epitaxial layer.

OBJECTS OF THE INVENTION The present invention solves these conventional drawbacks, and aims to improve the vapor phase of an epitaxial layer, which does not undergo autodoping from a susceptor and can obtain a uniform k Et'- doped layer. The purpose is to provide a way to grow.

Structure of the Invention In order to achieve the above-mentioned object, the present invention provides ? An epitaxial method in which a crystal plate having an upper surface of a size that does not protrude beyond the single crystal substrate described in I'Q is provided, and the crystal material 11 is sent in a vapor phase to grow crystals on the L+i crystal substrate. A method for vapor phase growth of layers is provided. .

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 to 5.

As shown in FIG. 2, according to one embodiment of the present invention, the susceptor (single crystal substrate 13 between the phantom and the single crystal substrate (3)) protrudes inside the vertical reaction tube +11. Arrange the knot plate (4) with a top surface of a size that is not large, and react w (
In step 1), a semiconductor crystal material was flowed in a vapor phase in the direction of arrow (2), and crystal growth was performed at a temperature of 700° C. for 1 hour. Note that GaAs was used as the material for both the single crystal substrate (3) and the crystal plate (4). In addition, single crystal substrate (3)
is a square with − sides of 1-511.

The results of crystal growth performed under the above conditions using the apparatus having the above configuration are shown in X in FIG. For comparison, crystal growth was carried out under the same conditions using the apparatus shown in FIG. 1, and the results are also shown in FIG. 8 by Y. As can be seen from FIG. 8, in the configuration shown in FIG. 1, the epitaxial layer formed on the single crystal substrate (3) has an average thickness of 6 μm in the central portion, but the thickness of the epitaxial layer in the peripheral portion 2WM is approximately 1 μm. ．It has grown about three times as thick. On the other hand, in the case of the structure shown in Figure 2, the average thickness of the epitaxial layer is slightly smaller at 54 μm, but the in-plane uniformity is very good, and the difference between the maximum and minimum thickness is about 0.
．． At the same time, the susceptor (2) becomes extremely small at 8 μm.
No deterioration of the electrical or optical properties of the epitaxial layer due to autodoping was observed.

In order to more accurately evaluate the present invention, the growth rate of the epitaxial layer was varied from 0.01 μm/min to 1 μm/min.
A large number of epitaxial layers having a growth thickness of 6 μm to 10 μm were fabricated, and similar results were obtained for all of them. That is, using the configuration shown in Figure 2 (A), a highly uniform epitaxial layer with an in-plane variation in the grown film thickness of ±5% or less was obtained, and improvements in its electrical and optical properties were also observed. There wasn't.

In addition, in the 211th configuration, the vertical reaction tube (1) is used (・
However, as shown in FIG. 4, it is also possible to use a horizontal reaction tube. In addition, a single crystal substrate (3) and a crystal plate (4)
GaAs was used as the material, but InP, GaSb
.

Other compound semiconductors such as GaP, ZuSe, ZnS, and Si.

All semiconductor materials can be used, including Ge and the like.

Effects of the Invention As described above, according to the vapor phase growth method of the present invention, by interposing a crystal plate between a susceptor and a single crystal substrate, uniform epitaxial growth without deterioration of electrical and optical properties can be achieved. layers can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional apparatus used for vapor phase growth of an epitaxial layer, FIG. 2 is a sectional view showing a configuration according to an embodiment of the present invention, and FIG. 3 is a sectional view showing the position on a substrate. FIG. 4 is a graph showing the relationship between the thickness of the epitaxial layer and the thickness of the epitaxial layer formed, and FIG. 4 is a cross-sectional view showing another embodiment of the present invention. (2)...Susceptor, (3)...Single crystal substrate, (4
)...Crystal plate (8)...Gas flow agent of crystal material Yoshihiro Morimoto

Claims (1)

[Claims] 1. A crystal plate having an upper surface large enough not to protrude at least the single crystal substrate is disposed between the single crystal substrate and the susceptor, and the crystal material is delivered in a vapor phase onto the single crystal substrate. A vapor phase growth method for epitaxial layers that allows crystal growth. −