JPS63188934A - Vapor growth system - Google Patents

Abstract

PURPOSE:To execute a cleaning process by only exchanging an auxiliary pipe by a method wherein the auxiliary pipe covering the upper face inside a reaction chamber is installed to be detachable in relation to the reaction chamber. CONSTITUTION:A cylindrical auxiliary pipe 40 whose cross section is like a semicircular arc is installed at a reaction chamber 20; the auxiliary pipe 40 covers the upper part of the reaction chamber 20 where a susceptor 22 is mounted; if a side plate 41 is detached, the auxiliary pipe 40 can be detached or installed after sliding the auxiliary pipe 40 on a pipe wall 21a of a quartz reaction pipe 21. Because a reaction gas and a dopant gas are introduced into a reaction chamber 25a near a sapphire substrate 24 while a first reaction-gas pipe 25 is separated from a second reaction-gas pipe 26, a reaction is restrained and a good doping process is executed. Although soot generated during the reaction process adheres to the auxiliary pipe, it is enough to exchange this auxiliary pipe for a cleaned auxiliary pipe for a cleaning process; it is easy to clean the reaction chamber.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a vapor phase growth apparatus using an organometallic compound gas with improved usability.

[Prior art]

Conventionally, organometallic compound vapor phase epitaxy (hereinafter referred to as "MOVPEJ")
gallium nitride-based compound semiconductor (Aj
! Vapor phase growth of thin films (xGa+−xN; including X=0) on sapphire substrates has been studied. This method is carried out using a vapor phase growth apparatus as shown in FIG. In the vapor phase growth apparatus, a quartz reaction tube 7
A manifold 6 is connected to the manifold 6, and the manifold 6 has a supply system A for NHs, a supply system B for H, N, and a supply system for trimethyl gallium (hereinafter referred to as rTMGJ), an organometallic compound gas. C, a supply system for trimethylaluminum (hereinafter referred to as rTMAJ), which is an organometallic compound gas, and a supply system for diethylzinc (hereinafter, referred to as rDEZJ), which is a reactive gas containing a doping element (hereinafter simply referred to as "dopant gas"). E is connected. Further, a graphite susceptor 9 for high frequency heating is arranged inside the quartz reaction tube 7, and the susceptor 9
A sapphire substrate 10 is placed thereon, and the sapphire substrate 10 is heated by the high frequency coil 8. Reaction gases and carrier gases are mixed in a manifold 6 from each supply system, and the mixed gas is led to a quartz reaction tube 7 and blown onto a sapphire substrate 10, thereby growing a thin film of AlxGa+-xN on the sapphire substrate 10. Then, by changing the mixing ratio of each organometallic compound gas, the composition ratio can be changed, or by doping with zinc, I
A thin film of type Al1xGal-xN can be formed.

[Problems to be solved by the invention]

In this way, in conventional equipment, the crystal growth of Al1xGal-1IN is performed at a high temperature of about 1000°C, so the reaction gas TMG or triethyl gallium (rTEG
(denoted as J) decomposes and carbon-like soot is produced in the quartz reaction tube 7.
There is a problem that the attached soot is incorporated into the crystal and acts as an impurity. In order to solve this problem, conventionally the quartz reaction tube 7 was removed and washed by placing it in HF water. However, since the quartz reaction tube 7 is large, it is complicated to remove it, and it is also expensive, so great care must be taken to avoid damage. The present invention was made to solve the above problems, and its purpose is to improve the usability of a vapor phase growth apparatus.

[Means to solve the problem]

The structure of the invention to solve the above problem is that, in a vapor phase growth apparatus using an organometallic compound gas, an auxiliary pipe is provided that can be attached to and detached from the reaction chamber to cover at least the upper surface of the inside of the reaction chamber. .

[Effect]

The soot generated by the reaction adheres to the auxiliary pipe that covers at least the upper surface of the reaction chamber. Since this auxiliary tube is detachably attached to the reaction chamber, only this auxiliary tube needs to be replaced when cleaning the reaction chamber. This auxiliary tube can be made smaller than the quartz reaction tube, so it can be easily attached and detached. Further, since the next crystal growth can be performed immediately by simply replacing the auxiliary tube with a new one, manufacturing efficiency is also improved.

【Example】

The present invention will be described below based on specific examples. FIG. 1 is a sectional view showing the structure of a vapor phase growth apparatus according to a specific embodiment of the present invention. In a reaction chamber 20 surrounded by a circular quartz reaction tube 21, a susceptor 22 is supported by an operating rod 23, and the position of the susceptor 22 is adjusted by the operating rod 23. Further, a sapphire substrate 24 is disposed on the main surface of the susceptor 22. Note that 8 is a high frequency coil for heating the sapphire substrate 24. On the other hand, on the gas inflow side of the reaction chamber 20, a first reaction gas pipe 25 and a second reaction gas pipe 26 are arranged. The first reaction gas pipe 25 is arranged concentrically with the second reaction gas pipe 26 inside the second reaction gas pipe 26 . The first reaction gas pipe 25 is connected to a first manifold 27 , and the second reaction gas pipe 26 is connected to a second manifold 28 . The 17th second hold 27 has a supply system H for NH.
and carrier gas supply system I and TMG supply system J and T
is connected to the MA supply system, and the second manifold 28
A carrier gas supply system I and a DEZ supply system stop are connected to. Further, an auxiliary tube 40 having a cylindrical shape and a semicircular arc cross section is disposed in the reaction chamber 20. As shown in FIG. 2, the auxiliary tube 40 has its bottom portions 40a and 40b in contact with the tube wall 21a of the quartz reaction tube 21, and is supported by the tube wall 21a. The auxiliary pipe 40 covers the upper part of the reaction chamber 20 in which the susceptor 22 is placed. Then, by removing the side plate 41 and sliding the auxiliary tube 40 on the tube wall 21a of the quartz reaction tube 21, it can be removed or installed in the reaction chamber 20. With such an apparatus configuration, a mixed gas of NHs, TMG, TMA, and H3 flows into the reaction chamber 20 from the opening 25a of the first reaction gas pipe 25, and flows out from the opening 26a of the second reaction gas pipe 26. , DEZ(!: H2 flows out into the reaction chamber 20. When forming an N-type Al,lG a +-x NU film, the mixed gas flows out only from the first reaction gas pipe 25. In the case of forming a type AβxGa'+-xN thin film, the first reaction gas pipe 25 and the second reaction gas pipe 2 may be
It is sufficient if the respective mixed gases are allowed to flow out from 6 and 6. In the case of forming a type (2) type Al
It will be mixed for the first time in a. Then, DEZ is sprayed onto the sapphire substrate 24 and thermally decomposed, and the dopant element is doped into the growing AlxGa+-xN to form ■-type Aj! xGa1-xN is obtained. in this case,
Since the reaction gas and the dopant gas are separated by the first reaction gas pipe 25 and the second reaction gas pipe 26 and guided to the reaction chamber 25a near the sapphire substrate 24, the DEZ in the gas introduction pipe that occurs in the conventional device is Since the reaction with TMG or TMA is suppressed, good doping is achieved. Incidentally, the inclination angle θ of the susceptor 22 with respect to the flow direction X of the reaction gas is set to 45 degrees. By tilting the susceptor 22 in this manner, better crystals were obtained than when the susceptor 22 was configured perpendicular to the gas flow. Further, it is desirable that the distance between the openings 25a, 26a and the sapphire substrate 24 be adjusted to 10 to 60 mm using the control rod 23. In addition, in the above embodiment, the first reaction tube and the second reaction tube are set so that the dopant gas is not mixed with other reaction gases.
It is introduced up to the vicinity of the sapphire substrate 24, and the ■ type A
j! The crystallinity of xGa+-xN improves, but if this effect does not need to be produced, the dopant gas is mixed with other reaction gases in a manifold in advance and introduced into the reaction chamber, as in conventional equipment, and then tilted. It may also be sprayed onto the main surface 24a of the sapphire substrate 24. With such a device, you can get high quality Aji! xGa+-xN thin films can be grown in vapor phase. If soot adheres to the auxiliary pipe 40, remove the side plate 41 and remove the auxiliary pipe 40 inside.
If you take it out and replace it with another cleaned auxiliary tube, you can immediately start growing the next crystal.

【Effect of the invention】

In a vapor phase growth apparatus using organometallic compound gas, the present invention is provided with an auxiliary tube that covers at least the upper surface of the inside of the reaction chamber and is detachable from the reaction chamber, so that the soot generated during the reaction process is removed from the auxiliary tube. At the time of cleaning, this auxiliary tube can be replaced with another cleaned auxiliary tube, which has the effect of facilitating cleaning of the reaction chamber.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the configuration of a vapor phase growth apparatus according to a specific embodiment of the present invention. FIG. 2 is a sectional view of the reaction chamber in the device. FIG. 3 is a block diagram showing the structure of a conventional vapor phase growth apparatus. 7...Quartz reaction tube 8...High frequency coil 9°...
Susceptor 10...Sapphire substrate 20...
Reaction chamber 21゛゛Quartz reaction tube 22゛...Susceptor 2
3°・“Control rod 24...Sapphire substrate 25...
...First reaction gas pipe 26...°Second reaction gas pipe 27
...First manifold 28...Second manifold 40...Auxiliary pipe 41 ・Side wall Ho・"NH
s supply system Io...°Carrier gas supply system J
...TMG supply system K...TMA supply system L...DEZ supply system Patent applicant Toyota Gosho Co., Ltd. President of Nagoya University

Claims (1)

[Scope of Claim] A vapor phase growth apparatus using organometallic compound gas, characterized in that an auxiliary tube that covers at least the upper surface of the inside of the reaction chamber is detachably attached to the reaction chamber.