Single-crystal – oriented-crystal – and epitaxy growth processes; – Apparatus
Reexamination Certificate
1999-02-09
2001-01-16
Utech, Benjamin L. (Department: 1765)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Apparatus
C118S7230AN
Reexamination Certificate
active
06174367
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to an epitaxial system, and especially to an organometallic vapor-phase epitaxial system.
BACKGROUND OF THE INVENTION
A general organometallic vapor-phase epitaxial system is commonly used for the growth of IIIA-VA compounds. For a nitride epitaxy, it is required to use ammonia as a reaction source of nitrogen. However, ammonia is reactive only under high temperature. As the growth temperature is increased, the demand for the saturated vapor pressure of nitrogen for the growth of gallium nitride is increased. It brings about an increased depletion of ammonia but the effective reaction amount of nitrogen does not increase. In addition, the epitaxial system using ammonia has some disadvantages as follows:
1. During the growth of P-type III-V compound, the coverage by hydrogen is occurred, resulting in that P-type III-V compound is under a high isolated state. Therefore, it needs another treatment for recovering the P-type electrical conductivity.
2. Ammonia easily causes a comsumption of graphite and vacuum-required oil, and a damage of the vacuum tube and the system so that it is an uneasy task to maintain the system.
In another organometallic vapor-phase epitaxial system using the electron cyclotron resonance (ECR), IIIA and VA elements are provided from different tubes and then react with each other to produce an epitaxial growth on the surface of the wafer substrate. However, it still has some defects:
1. After the VA elements leave the electron cyclotron resonance, they will easily return to the molecule state (e.g. N
2
). Therefore, the effective amount for forming the IIIA-VA compound is quite less than its consumed amount of the initial reactant.
2. The wafer substrate can not be heated to a higher temperature so that the crytallization of the epitaxial layer is not good enough.
Therefore, it is desirable to develop a device or method to solve the problems encountered by the applicant.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an epitaxial system adapted to be used for performing an epitaxial growth of IIIA-VA compound on the wafer substrate.
According to the present invention, the epitaxial system includes a first reaction region for providing a plasma of a first reactant, a second reaction region for epitaxially reacting the plasma of the first reactant with a second reactant on a wafer, and a guiding medium disposed between the first reaction region and the second reaction region for passing therethrough the second reactant and the first reactant plasma to the second reaction region.
In accordance with one aspect of the present invention, the first reaction region includes a high radiation frequency plasma generator.
In accordance with another aspect of the present invention, the first reactant is a substance containing one of VA elements.
In accordance with another aspect of the present invention, the first reactant is one selected from a group consisting of ammonia, nitrogen, arsenic, arsine (AsH
3
), phosphorus, phosphorus trihydride (PH
3
) and a mixture thereof.
In accordance with another aspect of the present invention, the second reaction region includes a medium radiation frequency heater for controlling a temperature of the wafer ranged from room temperature to 1200° C.
In accordance with another aspect of the present invention, the second reactant is one selected from a group consisting of IIIA organometallic compounds.
In accordance with another aspect of the present invention, the second reactant is a gallium-containing compound.
In accordance with another aspect of the present invention, the guiding medium is a multi-hole tube.
In accordance with another aspect of the present invention, the multi-hole tube is disposed between the first reaction region and the second reaction region in a horizontal arrangement.
In accordance with another aspect of the present invention, the epitaxial system further includes a gas container to provide a carrier gas for carring the first reactant and the second reactant.
In accordance with another aspect of the present invention, the epitaxial system further includes a gas flow controller for controlling flow rates of the first reactant, the second reactant, and the carrier gas.
In accordance with another aspect of the present invention, the epitaxial system further includes an electronic pressure controller to control the gas flow controller.
In accordance with another aspect of the present invention, the epitaxial system further includes a vacuum pumping system controlled by the electronic pressure controller for adjusting a pressure of the epitaxial system.
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patent: 4-26597 (1992-01-01), None
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Chan Shih-Hciung
Chang Chun-Yen
Guo Jan-Dar
Lai Wei-Chi
Tsang Jian-Shihn
Anderson Matthew
National Science Council
Utech Benjamin L.
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