JPH01218010A - Vapor growth method and apparatus, and method of cleaning reactor in apparatus - Google Patents

Abstract

PURPOSE:To prevent any impurity from adhering to a substrate and a reactor inner surface by providing an ion source on part of a reactor to etch the substrate and clean the reactor inner surface. CONSTITUTION:An ion source 12 is provided on part of a reactor 1. A substrate 7 made of GaAs is etched by placing the substrate 7 on a susceptor 5 and putting the susceptor in the reactor 1, and further keeping the reactor l blocked from the atmosphere by closing a gate valve 4 and feeding etching gas activated in the ion source 12 into the reactor 1. A gate valve 14 disposed under the ion source 12 is opened to etch and clean a crystal of GaAs or AlGaAs adhering to the inner surface of the reactor 1 using an Ar ion and chlorine from the ion source 12. Hereby, any impurity is prevented from adhering to the substrate 7 and the reactor 1 inner surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vapor phase growth apparatus, a method for cleaning its reactor, and a vapor phase growth method.

[Prior art] Arsine ASH3 of group ■ and trimethyl gallium G of group ■
a (CH3) 3 (hereinafter referred to as TMG).

Trimethylaluminum Aβ(CH3)3' (hereinafter T
GaAS and Aβ are deposited on a GaAS substrate using
Organometallic chemical deposition method for crystal growth of thin films of GaΔS (
A vapor phase growth method (hereinafter referred to as MOCVD method) has recently attracted attention as a method for manufacturing high-speed electronic devices and optical devices. Such a vapor phase growth method usually uses GaA
After etching the surface of the S substrate by soaking it in an etching solution, washing it with pure water and draining it,
The substrate is placed on a susceptor in a prechamber of a vapor phase growth apparatus, and then the susceptor is moved into a reactor of the vapor phase growth apparatus, and the above-mentioned vapor phase growth process is performed while being heated to a high temperature by high frequency heating in this reactor. The crystal growth is performed on the substrate by flowing the gas. As a heating method, in addition to high-frequency heating, there is a method in which an infrared heater is placed inside the susceptor. ASH3 and H2 in the reactor before crystal growth
Baking is sometimes performed for a while to remove impurities that have adhered to the substrate due to exposure to air.

[Problems to be Solved by the Invention] However, in the conventional vapor phase growth method, the surface of the substrate is exposed to the atmosphere after being etched, so oxygen and moisture in the atmosphere adhere to the surface of the substrate, which causes impurities. Therefore, there was a problem that the crystal growth was inhibited.

In addition, in the conventional method, when vapor phase growth is repeated, GaAs crystal growth occurs on the inner surface of the reactor and the susceptor.
There is a problem in that if this peels off due to the gas flow and falls onto the substrate, it will cause surface defects.

Furthermore, even if the substrate is baked in the reactor, if impurities generated at that time adhere to the surface of the reactor or susceptor, the baking will not be effective.

The object of the present invention is to provide a vapor phase growth apparatus that can prevent the substrate from being exposed to the atmosphere after etching the substrate, and that can easily clean the inner surface of the reactor, a method for cleaning the reactor, and a vapor phase growth method. Our goal is to provide the following.

[Means for Solving the Problems] The means of the present invention for achieving the above object will be explained.

The vapor phase growth apparatus according to claim (1) is characterized in that an ion source is provided in a part of the reactor. With the inside of the reactor isolated from the atmosphere,
The vapor phase growth method according to claim (3), characterized in that an etching gas activated by an ion source is supplied into the reactor to clean the inner surface of the reactor. The method is characterized in that the substrate is etched by supplying an etching gas activated by an ion source into the reactor with a susceptor inserted and the inside of the reactor isolated from the atmosphere.

[Function] When an ion source is provided in the reactor, etching of the substrate and cleaning of the reactor can be performed together, and the substrate and the inner surface of the reactor are not exposed to the atmosphere after the processing is completed.

When an etching gas activated by an ion source is supplied into the reactor while the inside of the reactor is isolated from the atmosphere,
The inside of the reactor can be cleaned. Moreover, by doing this, the inner surface of the reactor is not exposed to the atmosphere during or after cleaning.

The substrate can be etched by placing a susceptor carrying a substrate in a reactor and supplying etching gas activated by an ion source to the reactor while the reactor is isolated from the atmosphere. After etching, the substrate is not exposed to the atmosphere.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In the figure, 1 is a quartz glue actor, 2 is a reactor 1
5 is a susceptor that moves within the reactor 1 and the prechamber 2, 6 is a shaft that moves the susceptor 5 up and down and rotates, and 7 is a shaft on the susceptor 5. 8 is a water cooling jacket provided on the outer periphery of the reactor 1, 9 is a high frequency coil as a heating source provided on the outer periphery of the reactor 1, and 10 is a gas pipe connected to the upper side of the reactor 1. , 11 is a trachea provided in the exhaust section 3, 12 is an electron cyclotron resonance ion source connected to the upper end of the reactor 1 via a connection section 13 and a gate pulp 14, and 15 is a conductor connected to the ion 81i12. Wave tube, 16, cold water pipe for cooling the ions 11112, 17
is an etching gas pipe for supplying etching gas to the ion source 12.

Next, a vapor phase growth method involving etching of the substrate 7 using such an ion source 12 and a method of cleaning the inner surface of the reactor 1 will be described.

Aeon II! 12 uses microwaves (2,450 IIZ) supplied from a waveguide 15, and when the microwaves are introduced while sending etching gas into the ion source 12 from the pipe 17, the etching activated in the ion source 12 is activated. Gas is supplied into the reactor 1. When Ar is used as the etching gas and chlorine CJ22 is further mixed, Ga
AS etching speed becomes faster.

Etching of the substrate 7 made of GaAS was carried out by placing the substrate 7 on the susceptor 5 in the reactor 1, closing the gate valve 4 to isolate the inside of the reactor 1 from the atmosphere, and activating the substrate 7 with the ion source 12. This is carried out by supplying etching gas into the reactor 1. After etching is completed, purging is performed by supplying 142 or N2 from the gas pipe 10 into the reactor 1. During such purging, the gate valve 14 located at the bottom of the ion source 12 is closed.

After purging, N2 and ASH3 are flowed through the susceptor 5 or while directly heating the substrate 7 to further perform high-temperature purging. Thereafter, TMG or TMA is flowed into the reactor 1 from the gas pipe 10 to perform thin film crystal growth on the substrate 7.

When the crystal growth is finished, the inside of the reactor 1 is purged in the same manner, and then the susceptor 5 and the substrate 7 are lowered into the prechamber 2 by listening to the gate valve 4, and then the gate valve 4 is opened again.

Next, by opening the gate valve 14 below the ion source 12, Ar ions and chlorine are used from the ion source 12 in the same manner as described above to remove the GaAs crystals or Al
J! Etch and clean the GaAs crystal. The etched material is removed from the exhaust pipe 11 of the exhaust section 3. Note that hydrogen is flowing from the gas pipe 10 at this time. Further, when the ion source 12 is operated, the pressure inside the reactor 1 is set to a low gas pressure of about 10-2 [Pa. After this etching, the pressure inside the reactor 1 is set to a desired pressure to perform crystal growth or purging.

As an etching gas, in addition to C12, HC and GaA are used.
It is effective for etching S.

As the ion source 12, a Kauffman type ion source may be used in addition to an electron cyclotron resonance type ion source using microwaves.

ion? 1112 does not have to be attached directly above the reactor 1, but may be attached somewhat to the side of the reactor 1.

ASSi using carrier gas 12 from gas piping 10
When sending 20TMG and TMA to the reactor 1, if they enter the ion source 12, it will not be good for the apparatus, so it is preferable to close the gate valve 14 when not etching.

The susceptor 5 may be a barrel type for growing a large number of substrates 7.

The susceptor 5 may be made of quartz instead of carbon, and an infrared heater may be placed inside the susceptor 5 to achieve the same effect. In this case, since there are only the substrate and quartz glass inside the reactor 1, a clean atmosphere is created, and the quality of the crystal is further improved.

[Effects of the Invention] Since the present invention is as described above, the following effects can be obtained.

In the vapor phase growth apparatus according to claim (1), since the ion source is provided in a part of the reactor, etching of the substrate and cleaning of the inner surface of the reactor can be performed together. Such etching and cleaning can be performed with the inside of the reactor isolated from the atmosphere, which has the advantage that the substrate and the inner surface of the actuator are not exposed to the atmosphere after the processing is completed, and the adhesion of impurities can be prevented.

The method for cleaning a reactor of a vapor phase growth apparatus according to claim (2) includes: with the inside of the reactor being shut off from the atmosphere;
Since the etching gas activated by the ion source is supplied into the reactor, the inner surface of the reactor can be cleaned. If you lean like this,
There is an advantage that the inner surface of the reactor is not exposed to the atmosphere during or after cleaning. Additionally, cleaning in this way will remove the GaAS that adheres to the inside of the reactor.
The crystals such as AλGaAs and AλGaAs can be removed, and crystal growth can be performed on the substrate in a new reactor at any time. Furthermore, cleaning the reactor prevents crystals from peeling off from the inner surface of the reactor and falling onto the substrate, thereby improving the surface quality of the substrate after crystal growth.

In the vapor phase growth method according to claim (3), a susceptor carrying a substrate is placed in a reactor, and an ion beam obtained by ionizing etching gas with an ion source is supplied into the reactor, so that the etching of the substrate is carried out within the reactor. This can prevent the substrate from being exposed to the atmosphere after etching and impurities from adhering to it. Therefore, it is possible to improve the crystal quality of the substrate. Further, according to the present invention, the etching process using an etching solution can be eliminated, and the entire process from etching to crystal growth can be performed within the reactor, thereby improving productivity.

[Brief explanation of the drawing]

The drawing is a longitudinal cross-sectional view of a main part showing an example of a vapor phase growth apparatus that implements the present invention. DESCRIPTION OF SYMBOLS 1...Reactor, 2...Prechamber, 3...Exhaust part, 4...Gate valve, 5...Susceptor, 6...
... Shaft, 7... Board, 9... High frequency coil,
10... Gas piping, 12... Ion source, 14...
Gate valve, 15... waveguide, 17... etching gas piping.

Claims (3)

[Claims] (1) In a vapor phase growth apparatus in which a substrate is placed on a susceptor in a reactor and a gas for vapor phase growth is flowed into the reactor to cause crystal growth on the substrate, an ion source is provided in a part of the reactor. A vapor phase growth apparatus characterized by: (2) In the reactor cleaning method for a vapor phase growth apparatus, in which a substrate is placed on a susceptor in a reactor, and a gas for vapor phase growth is caused to flow into the reactor to cause crystal growth on the substrate, the inside of the reactor is removed from the atmosphere. With it shut off,
1. A method for cleaning a reactor of a vapor phase growth apparatus, the method comprising cleaning the inner surface of the reactor by supplying an etching gas activated by an ion source into the reactor. (3) In a vapor phase growth method in which a substrate is placed on a susceptor in a reactor and a gas for vapor phase growth is flowed into the reactor to cause crystal growth on the substrate, the susceptor with the substrate placed in the reactor. A vapor phase growth method characterized in that the substrate is etched by supplying an etching gas activated by an ion source into the reactor with the inside of the reactor shut off from the atmosphere.