JPH01205428A - Vapor phase epitaxial growth equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Summary] Regarding a light irradiation type vapor phase epitaxial growth apparatus, decomposition products of an epitaxial growth gas are deposited on the inner wall of a reaction tube for epitaxial growth, and light from a light source for epitaxial growth enters the reaction tube. The aim is to provide an apparatus that prevents the epitaxial growth from becoming difficult to pass through the system. a light source that irradiates the substrate from outside the reaction tube and decomposes the epitaxial growth gas; A partition plate is provided at a predetermined interval from above the substrate, substantially parallel to the introduced gas flow, and at a predetermined interval from above the substrate, and the epitaxial growth gas is introduced between the substrate and the partition plate. , the wall of the reaction tube is tapered so that the gas after evixaxial growth passes over the partition plate and flows along the inner wall of the reaction tube that is irradiated with the light source.

[Industrial application field]

The present invention relates to a light irradiation type vapor phase epitaxial growth apparatus.

Mercury/ISmium/tellurium (l1g 1-
A compound semiconductor crystal of 11g1-xCdXTe is used, and it is necessary to obtain such a crystal of 11g1-xCdXTe in a large area and in a thin film for convenient device formation.

As a method that does not meet these requirements, a substrate of cadmium telluride (cdTe) housed in a reaction tube is used, such as cynochloride ((CIl:l)zcd) or diethyltellurium ((Cllzll,)zTe). Epitaxial growth gas is introduced, the substrate is heated to decompose the epitaxial growth gas, and the decomposed components are deposited on the substrate.
rganic Chemical Vapor Depo
A metal-organic chemical vapor deposition (organic metal chemical vapor deposition) method is used.

In such MOCV I) method, the epitaxial growth substrate is irradiated with ultraviolet rays to accelerate the decomposition rate at which the epitaxial growth gas decomposes and adheres to the substrate, thereby lowering the growth temperature of the substrate. Phase growth methods have recently been used.

[Conventional technology]

Normally, in such a photo-vapor phase growth apparatus, decomposition products of the epitaxial growth gas adhere to the inner wall of the reaction tube, and this product obstructs the transmission of light from the light source, reducing the efficiency with which light reaches the substrate. Become.

Therefore, devices have been proposed that prevent such decomposition products from adhering to the inner wall of the reaction tube.

The second method is a device that prevents the reaction products of epitaxial growth residue from adhering to the inner wall surface of the reaction tube.As shown in the figure, a susceptor 3 with a substrate 2 for epitaxial growth installed inside the reaction tube 1 is installed. A light a4 for irradiating the substrate with ultraviolet rays is installed outside of 1.

Furthermore, a gas introduction pipe 5 through which epitaxial growth gas flows is provided in the central region where the substrate 2 is installed when viewed from the diameter direction of the reaction tube 1, and furthermore, high temperature hydrogen gas flows along the upper direction of the reaction tube. A gas introduction pipe 6 is provided,
Furthermore, a gas introduction pipe 7 is provided at the bottom of the reaction tube through which low-temperature hydrogen gas flows.

In this way, by flowing a separate gas that does not contain the components of the growth gas above and below the epitaxial growth gas, the epitaxial growth gas is prevented from coming into contact with the inner wall of the reaction tube, and the decomposition products of the epitaxial growth gas are prevented. Prevent it from adhering to the inner wall of the reaction tube.

[Problem to be solved by the invention] In addition to the above epitaxial growth gas,
With conventional equipment in which a gas for removing decomposition products from the inner wall of the reaction tube is separately introduced into the reaction tube, it is difficult to precisely control the concentration of the epitaxial growth gas by the introduced gas, and it is difficult to achieve the desired composition. There is a problem that epitaxial crystals cannot be formed with high precision.

Furthermore, it is necessary to separately provide a gas introduction pipe to prevent products from adhering to the reaction tube, resulting in a complicated structure of the apparatus.

The present invention aims to eliminate the above-mentioned problems and provide a vapor phase epitaxial growth apparatus in which reaction products do not adhere to the inner wall surface of a reaction tube.

[Means for Solving the Problems] The vapor phase epitaxial growth apparatus of the present invention that achieves the above object has an epitaxial growth substrate 1 as shown in the first part.
1, a gas introduction tube 14 connected to the reaction tube 13 and introducing gas for epitaxial growth, and a gas exhaust tube 15 discharging the gas after epitaxial growth. Substrate 1-,
rA+ light that irradiates and decomposes the epitaxial growth gas
6, and a partition plate 17 which is housed in the reaction tube and whose longitudinal ends have a predetermined distance from the vertical wall surface of the reaction tube, and which has a predetermined distance from the substrate-1.
, the epitaxial growth residue is introduced between the substrate and the partition plate, and the epitaxial growth residue passes over the partition plate and is tapered (18A, 1f311) so that it flows along the inner wall of the reaction tube that is irradiated with the light source. ．．
18C) was provided on the inner wall of the reaction tube.

[For production]

The apparatus of the present invention uses a gas for preventing reaction products from adhering to the inner wall surface of the reaction tube that is irradiated with light, without introducing a gas separate from the epitaxial growth gas into the reaction tube. The reflux gas is refluxed along the substrate and the epitaxial growth gas introduced into the reaction tube is in such a state that the direction of the gas flow changes as they interact with each other at the substrate. The gas prevents heat from the substrate or susceptor from being transferred to the inner wall of the reaction tube.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a vapor phase epitaxial growth apparatus of the present invention.

As shown in the figure, a susceptor 12 made of quartz or graphite on which a CdTe substrate 11 for epitaxial growth is installed is housed inside a reaction tube 13 . A gas introduction tube 14 is provided horizontally at one end of the reaction tube 13.
A gas exhaust pipe 15 is provided at the other end of the gas discharge pipe 3 in a vertical direction. The substrate 12 is placed on the substrate 12 at a predetermined distance i, in a direction substantially parallel to the flow of gas introduced from the gas introduction tube 14, and at a predetermined distance d from the inner wall surfaces of both ends of the reaction tube 13. A partition plate 17 made of quartz and having an opening at the top of the substrate is provided.

Also, the upper and lower corner portions C3 of both ends of the reaction tube 13
1. The epitaxial growth gas introduced into the partition plate 17
Taper 12 (A,
181+ and 113c are provided. Furthermore, in order to prevent the introduced epitaxial growth gas from colliding with the end face of the susceptor 12 and generating a vortex of debris in that area, a quartz member 19 is installed so as to be continuous with the end face of the susceptor. Also, a substrate 1 is placed outside the reaction tube] 3 facing the substrate 11.
A light source for ultraviolet irradiation (1) is provided.

A case will be described in which a crystal of I1g+-XCdx Te is epitaxially grown on a CdTe substrate using the apparatus of the present invention.

A substrate 11 of CdT[4 is placed in the susceptor 2 described above, and the receptor 12 is inserted into a reaction tube 13, and then the inside of the reaction tube is evacuated to a degree of vacuum of about 10-5 LOrr.

Next, dinotyl cadmium gas supported on hydrogen gas as a carrier gas was introduced through the gas introduction pipe 14 at a partial pressure of 5X]0' atm, and diethyl tellurium gas supported on the hydrogen gas was injected at a partial pressure of 4 Xl0-' atm. In addition, hydrogen sludge is introduced into the sludge inlet pipe 14 in its own state, so that the total flow rate of the epitaxial growth gas becomes a value of 8 ρ/min.

Additionally, a heater (not shown) built into the susceptor 12
The temperature of the light source 1 is maintained at 300°C, and the light source 1 is
Irradiate ultraviolet light from step 6.

Then, the epitaxial growth gas introduced from the gas introduction pipe 14 is decomposed on the substrate by the heating of the susceptor, and the reaction is further promoted by a photochemical reaction caused by ultraviolet irradiation, and the decomposed epitaxial growth gas is The components adhere to the substrate as crystals.

Further, unreacted gas that does not participate in epitaxial growth moves along the taper 18B by hitting the end of the ζ reaction tube 13 in the direction of the arrow, and some of it is exhausted from the gas exhaust tube 15, but the unexhausted gas reaches the substrate 11 as shown by arrow B. On this substrate 11, an arrow C of the epitaxial growth gas introduced from the gas introduction pipe 14 is shown.
With respect to the direction of the gas flow shown in , the direction B of the gas flow that has passed through the lower part of the partition plate, collided with the end of the reaction tube, and refluxed to the upper part of the partition plate is different from the direction of the υJ gas flow.

The direction of this gas flow is 4'll due to mutually different gases,
2. (It becomes difficult for the heat from the plate or susceptor to reach the upper L wall G, and the upper part of the substrate does not reach the temperature of the scum, so the unreacted gas does not decompose in that area and the tube By passing through the wall, the reaction products of J gas no longer adhere to the reaction tube, and the light from the light source reaches the substrate sufficiently, eliminating the slow reaction phenomenon and stabilizing the K111 formation. An epitaxial crystal is formed on the substrate.

〔Effect of the invention〕

As is clear from the following explanation, according to the present invention, decomposition products of the evitaginal growth gas (;
Since the reaction tube does not become cloudy due to the adhesion of decomposition products, the photochemical reaction is not inhibited, so it is possible to obtain Epicure 1-Noyal crystals that do not cause compositional fluctuations. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a vapor phase epitaxial growth apparatus of the present invention, and FIG. 2 is an explanatory diagram of a conventional vapor phase epitaxial growth apparatus. In the figure, 11 is a cutting plate for epitaxial growth, 12 is a suction plate, 13 is a reaction tube, 14 is a gas introduction tube for epitaxial growth, 15 is a gas exhaust tube, 16 is a light source, 17 is a partition plate,
18A, 18B, and 18G are tapered, and 19 is a quartz part.

Claims (1)

[Scope of Claims] A reaction tube (13) that accommodates a susceptor (12) on which a substrate (11) for epitaxial growth is placed, and a gas introduction tube (13) that is connected to the reaction tube and that introduces a gas for epitaxial growth.
14), a gas exhaust pipe (15) for discharging the gas after epitaxial growth, a light source (16) for irradiating the substrate from outside the reaction tube and decomposing the epitaxial growth gas, and a light source (16) housed in the reaction tube (13). a partition whose longitudinal ends have a predetermined gap with respect to the vertical wall surface of the reaction tube (13), are substantially parallel to the gas flow to be introduced, and have a predetermined distance from the substrate. A reaction tube is provided with a plate (17), the epitaxial growth gas is introduced between the substrate (11) and the partition plate (17), and the gas after epitaxial growth passes over the partition plate and is irradiated with light. Taper (13) flowing along the inner wall of (13)
8A, 18B, 18C) on the inner wall surface of a reaction tube.