JPH05201791A - Liquid phase epitaxial growth method - Google Patents

Abstract

PURPOSE:To improve the yield by reusing a rest part of a growing thin film, separated from a single crystal substrate and the other part being made a product after liquid phase epitaxial growing with the single crystal substrate having a specific thickness, for the epitaxial growth. CONSTITUTION:A raw solution is prepared by adding a specific quantity of poly crystalline GaAs and Al into a compound semiconductor component of Ga or the like. The liquid phase epitaxial growth is executed by using the raw solution and a single crystal material having >=600mum thickness by the slide method with a boat for epitaxial growth. Next, the substrate part with the epitaxial growth layer thin film having about 300mum thickness is cut off from the single crystal substrate with a slicer or the like. The residual single crystal substrate is repeatedly reused for the liquid phase epitaxial growth. Thus, the yield of the compound semiconductor crystal thin film per an unit quantity of the raw single crystal is drastically increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid phase epitaxial growth method for compound semiconductors such as GaAs.

[0002]

2. Description of the Related Art Conventionally, a liquid phase epitaxial growth method by a slide method has been carried out by using a boat whose cross section is shown in FIG. (For example, Japanese Laid-Open Patent Publication No. 2-28920) A solution 3 as a raw material for growth is contained in an opening 2 of a solution reservoir 1, and a single crystal substrate 5 is provided while gradually cooling the entire boat.
The slider 7 on which is mounted is slid to sequentially bring the substrate into contact with each solution to grow an epitaxial layer having a multilayer structure. At this time, the single crystal substrate was produced by cutting out the single crystal raw material as shown in FIG.

[0003]

In the conventional growth method of this kind, a single crystal substrate having a thickness of about 300 μm is used, and the used substrate is treated as a product together with the grown thin film as it is, and is etched at the time of post-treatment. It was either thinner or removed. (FIG. 2) As described above, the thickness of the single crystal substrate does not need to be 300 μm due to the structure of the product.
In terms of operability during growth, it is necessary to have an extra thickness, which causes a decrease in the amount of a single crystal substrate obtained from a constant single crystal raw material and the amount of an epitaxial wafer manufactured using the single crystal substrate.

[0004]

In order to solve the above-mentioned problems, the present invention performs liquid phase epitaxial growth using a thick single crystal substrate, separates product parts, and then uses the substrate again for growth. The liquid phase epitaxial growth method is characterized in that

[0005]

Since liquid phase epitaxial growth is performed using a single crystal substrate having a thickness of 600 μm or more, the grown thin film can be easily separated from the single crystal substrate portion after growth to obtain a product. Since the remaining single crystal substrate has a sufficient thickness, it can be used again for epitaxial growth. Therefore, one substrate can be used for growth a plurality of times, and the number of epitaxial wafers that can be obtained from a certain amount of single crystal raw material can be dramatically increased as compared with the conventional case.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 3 shows a cross section of a boat for liquid phase epitaxial growth.
In the opening 2 of the solution reservoir 1, a solution 3 as a raw material for growth is
To house. A carbon plate 6 for adjusting the height of the substrate was placed in the single crystal substrate housing portion 4 and the single crystal substrate 5 was housed thereon.
If necessary, a plurality of carbon plates 6 for height adjustment may be used.

Epitaxial growth of AlGaAs was performed using this boat. The specific conditions are as follows. The size of the upper surface of the solution reservoir opening 2 is 33 mm x 33 m
m, and the thickness of the solution reservoir 1 was 10 mm. Solution 3 is Ga
Consisting of 80 mg of polycrystalline GaAs and 1 g of Ga
l2.5 mg was added. Ga as the single crystal substrate 5
The initial thickness was 30 mm using As. The amount of Ga solution was 40 g, the growth start temperature was 900 ° C., the cooling rate was 0.5 ° C./min, and the temperature was lowered to 500 ° C.

Since the finished product does not require a substrate portion, it was separated from the single crystal substrate portion leaving an epilayer portion having a thickness of about 300 μm. Although a wire saw was used for the separation, it may be cut with a slicer or the epi layer and the substrate may be separated by using a wedge or the like. This single crystal substrate was put again for epi growth and repeated growth was performed. As a result, 96 epi products could be manufactured. The manufacturing process from a single crystal raw material to an epi product based on the present invention is schematically shown in FIG.

In the embodiment, a single crystal substrate having an initial thickness of 30 mm is used, but it may be thicker or thinner than this as long as it has a thickness sufficient for reuse. However, if it is thinner than 600 μm, it can be reused only once or twice, so 600 μm or more is suitable. 400 μm if reuse once or twice is sufficient
Alternatively, it may be 500 μm.

For comparison, using conventional methods, a thickness of 3
When a substrate was first made from a 0 mm single crystal raw material, liquid phase epitaxial growth was performed using the substrate, and the substrate portion was removed by etching later, 45 epi products were obtained. FIG. 2 shows a manufacturing process of an epi product by a conventional method.

[0011]

According to the present invention, when an epitaxial wafer is manufactured using a certain amount of a single crystal raw material, the product can be manufactured without using a single crystal substrate having a thickness unnecessary for the structure of the product. Can be manufactured, and a large amount of products can be manufactured with a smaller amount of single-crystal raw material than in the past, and therefore it is very effective when used as a liquid phase epitaxial growth method.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a growth step by a liquid phase epitaxial growth method of the present invention.

FIG. 2 is a schematic view showing a growth step by a conventional liquid phase epitaxial growth method.

FIG. 3 is a cross-sectional view of a liquid phase epitaxial growth boat for explaining an example of the present invention.

[Explanation of Codes] 1: Solution Reservoir 2: Opening 3: Solution 4: Single Crystal Substrate Housing 5: Single Crystal Substrate 6: Carbon Plate for Height Adjustment 7: Slider

Claims (2)

[Claims] 1. A liquid phase epitaxial growth method for a compound semiconductor crystal by a slide method, which comprises using a single crystal substrate having a thickness of 600 μm or more. 2. A liquid phase epitaxial growth method for a compound semiconductor crystal by a slide method, wherein liquid phase epitaxial growth is performed using a single crystal substrate having a thickness of 600 μm or more, and then the grown thin film is separated from the single crystal substrate portion to obtain a product,
A liquid phase epitaxial growth method, characterized in that the remaining single crystal substrate is reused for epitaxial growth.