JPS63124410A - Vapor growth method - Google Patents

Abstract

PURPOSE:To obtain a great area and uniform epitaxial layer by making a gas form a laminar flow by making the raw gas flow between the growth surfaces of substrates provided face to face in a reaction tube. CONSTITUTION:H2, is made to flow in a reaction tube 1 and the pressure of the reaction tube is adjusted to a required value (38 Torr). The temperature of a carbon susceptor 3 is raised by applying voltage to a high frequency coil 2. When the temperature is raised to a required value (300 deg.C) or higher, PH3 is made to flow. When the temperature of the susceptor 3 is made 640 deg.C, an organic metal TEI is made to flow at 1 cc/min. An InP is epitaxially grown on a substrate 4 and a dummy substrate 5 provided face to face. Similarly, InGaAs, InGaAsP, etc., can be grown.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vapor phase growth method, and particularly to a vapor phase growth method suitable for uniform thin film crystal growth over a large area.

[Conventional technology]

The conventional device is rGa by T.P.Pearsall.
"InAsP Semiconductor" John, Willie Addsons, 1982, pp. 63-65 ("GaIrAsP Semiconductor")
lloy Sem1coHductors, “JOh
n Wiley & 5onS s 1982, p. 6
As described in 3-p. 65), a carbon susceptor was placed in the reaction tube and a substrate was placed on top of it.

[Problem that the invention seeks to solve]

In the prior art, the substrate inside the reaction tube was placed so as to face the tube wall. The influence of the tube wall was reduced by sometimes warming it or, conversely, cooling it. However, the effect was insufficient, and the substances adhering to the tube wall were re-evaporated, adversely affecting the growth layer. Furthermore, if the distance between the substrate surface and the tube wall is increased in an attempt to reduce these effects, the reaction tube will inevitably become larger and a large amount of raw material gas will be required, resulting in a problem of poor gas efficiency.

In addition, in the conventional technology, a susceptor heated to high temperature is placed in a round or square reaction tube having an appropriate diameter, and a substrate is placed on top of the susceptor to perform growth. The region through which the raw material gas flowed was spread over the entire interior of the reaction tube. The susceptor is placed in such a way as to obstruct the gas flow, and the gas flow is disturbed at that portion, making it difficult to obtain a uniform epitaxial layer over a large area.

Furthermore, since the gas was flowed over the entire surface of the reaction tube, a large amount of raw material gas was consumed, making it an inefficient growth method.

An object of the present invention is to eliminate the influence from the tube wall by facing the growth surfaces of the substrates and flowing a gas therein.

Another object of the present invention is to form a small duct-like part through which source gas flows, and to place a substrate on the inner surface of the duct, thereby making the gas laminar and producing a uniform epitaxial layer over a large area.

[Means for solving problems]

The above objective is achieved by placing the growth surfaces of the substrates in the reaction tube facing each other and flowing the raw material gas through the tube. be done.

[Effect]

Since the raw material is epitaxially grown on the growth substrate, re-evaporation of the raw material from there is extremely small.

Therefore, there is little adverse effect on other substrates.

Furthermore, since the raw material gas flows only in the duct within the reaction tube, the gas flow rate increases and the gas flow becomes laminar.

On the other hand, the thickness of the substrate placed in the duct is small and does not disturb the gas flow, so turbulence is less likely to occur.

Since the part through which the raw material gas flows can be made smaller than in conventional systems, more efficient growth can be achieved with a smaller amount of gas to obtain the same flow rate.

〔Example〕

An embodiment of the present invention will be described below.

Example 1 This will be explained with reference to FIGS. 1 and 2. FIG. 2 is a top view of FIG. 1.

First, H2 was flowed into the reaction tube 1 at a rate of 3.2 t/mm, and the pressure inside the reaction tube was adjusted to 38 Torr. A voltage is applied to the high frequency coil 2 to raise the temperature of the carbon susceptor 3.

If the temperature of the carbon susceptor reaches 300C or higher, press P.
Flow Ha at 250 cc/mix. Susceptor temperature is 6
When the temperature reaches 40C, organic metal TEI (triethyl indium) is flowed at l c c /min. In this way, IpP is epitaxially grown on the substrate 4.

When growing InGaAs, InGaAsP, etc., a source gas of an appropriate concentration may be flowed.

It is optimal for the dummy substrate 5 to have a substrate surface made of the same material as the substrate 4;
For example, InP, GaAs, Si, sapphire, and others may be used.

FIG. 3 shows a device that can charge a plurality of substrates 4.

Figure 4 shows an example in which a closed space is created using the substrate 4 and the dummy substrate 5, and the raw material is flowed into the space to create a laminar flow of gas.The gas concentration in the closed space can be made uniform, resulting in extremely good in-plane distribution. Epitaxial category.

FIG. 5 shows a case where the spacing between the substrates is made small. In particular, when a grating is formed on the surface, deterioration of the grating due to separation of P and the like is compensated for by the substrates 4 and 5, thereby preventing the deterioration. Good results can be obtained when the spacing is 5 to 5, and especially good when the spacing is around 1. When the grating is cut into InP, the combination of substrate 4 and substrate 5 is InP-I nP, I
Relatively good results are obtained with the combination of nP-GaAs.

Figure 6 shows a case where the number of closed spaces in Figure 4 is increased.In this way, the substrates can be efficiently arranged in a limited space, and the raw material gas flowing through the closed spaces can be made uniform, so that the number of closed spaces in Figure 4 can be increased. Able to grow multiple crystals with good distribution.

FIG. 7 shows a case where the substrates are arranged in a hexagonal shape and the raw material gas is flowed therein, but an n-gon shape may also be used.

Although the embodiments have been explained using a vertical reaction tube, the same applies to a horizontal reaction tube.

Example 2 This will be explained with reference to FIG. A total of 3174M of hydrogen gas is introduced from gas inlets A and B15°16.

A voltage is applied to the high frequency coil 10 to raise the temperature of the carbon susceptor 2. When the temperature reaches 3000 or more, 250 cc of PHa is introduced from the gas inlet B16. Substrate temperature is 640tl
: When the temperature reaches ', add 0.3 c c 7 m 1 tt of organometallic triethyl indium (TEI) from the gas inlet B16.
Flow PHa at 60 cc, Anm. Then, InP is epitaxially grown on the substrate 13. When growing other materials, it is sufficient to flow source gas at an appropriate concentration. It is desirable that the exhaust ports A, B 18 and 19 be adjusted so that the pressure inside the duct 14 is slightly lower than the pressure inside the reaction tube 11. By doing so, most of the raw material gas discharged from the gas supply port 17 flows into the duct, improving gas efficiency.

FIG. 9 shows an example in which two gas supply ports 17 are provided, and materials having different compositions are continuously grown by flowing and moving different raw material gases. At this time,
The same effect can be obtained by moving the board side. This allows the Peter interface to be made extremely steep.

Although FIG. 10 is an example in which the gas supply port 17 is omitted, there is an effect that the flow lines in the duct are not obstructed, so that laminar flow tends to occur. On the other hand, it has the advantage that it can be easily implemented in conventional equipment.

FIG. 11 shows an example in which a carbon susceptor is used on only one side of the duct, which is a simple method. 21 is a quartz cover, which is not shown in FIG.

Figure 12 shows an example in which two substrates are placed above and below in a duct, allowing two substrates to be grown at the same time, while reducing re-evaporation from hot wall decomposition products, making it possible to achieve high-purity epitaxial growth. . Se the wafer on the side too
t is more effective.

12 is a cover, which is not shown in FIG.

FIG. 13 shows an example in which the duct is tapered, and the taper angle is preferably about 1 to 10 degrees, which can further improve the in-plane uniformity of the gas in the traveling direction.

〔Effect of the invention〕

According to the present invention, it is possible to reduce the influence of the inner wall of the reaction tube on the epitaxial layer, thereby increasing the degree of freedom in design. Especially when flowing raw materials into a closed space surrounded by a substrate, it is highly efficient and uniform.
- Crystals with good properties can be obtained.

For example, when using a horizontal reactor with an inner diameter of φ80 mn,
With the conventional method, only one 2-inch substrate could be grown, but with the present invention, at least four substrates can be grown, and the in-plane distribution uniformity is ±10 inches to ±5% in film thickness, and ±5% in composition.
Each can be improved from 5% to ±2 inches.

The compositional steepness is 5 Å or less at the InP to InGaA3 growth interface and 10 Å or less at the InGaAS to InP growth interface, which is approximately half of the conventional method.

Further, according to the present invention, since the gas flow rate can be increased and laminar flow can be easily achieved, a uniform epitaxial film can be obtained over a large area. Variations in film thickness, composition variations, reproducibility, etc. can be reduced to 1/2 or less of conventional values. Even at the conventional gas flow rate, a uniform gas flow can be obtained because there is no obstacle to the streamlines, and the flow rate of the raw material gas can be reduced to 1/2 or less, so that the growth efficiency can be more than twice that of the conventional method under the same conditions.

Since the raw material gas is flowed locally, different materials can be grown continuously by slightly moving the raw material supply port or the substrate, and the steepness of the interface is about 5 people, which is half that of the conventional method.

Since the raw material gas is flowed locally, stains caused by reaction products are localized, and the number of cleanings is reduced compared to conventional products, making maintenance easier and lasting more than twice as long.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a top view of FIG. 1, and FIGS. 3 to 7 are top views of other embodiments. FIG. 8(a) is a cross-sectional view of the device, FIG. 8(b) is a cross-sectional view taken along line AA' in FIG. 8(a), and FIG. 9.10.13 is a cross-sectional view of another device. Figures 11 and 12 are A of Figure 10.
-A' sectional view. DESCRIPTION OF SYMBOLS 1... Reaction tube, 2... High frequency coil, 3... Carbon susceptor, 4... Substrate, 5... Dummy substrate, 1
0...High frequency coil, 11...Reaction tube, 12...
Carbon susceptor, 13... Substrate, 14... Quartz duct, 15... Gas inlet A, 16... Gas inlet B, 17... Gas supply port, 18... Exhaust sunlight, Engineering 9
...Exhaust port B, 21...Quartz plate.

Claims (1)

[Claims] 1. OMVP using reaction between organic metal and halide gas
A vapor phase growth method characterized by placing the growth surfaces of the substrates facing each other in a nearly symmetrical manner in the E method, and flowing a source gas between them. 2. OMVP using reaction between organic metal and halide gas
In the E method, a vapor phase growth method is characterized in that the part through which the raw material gas flows is formed into a small duct shape, and a substrate is placed on the inner surface of the duct.