JPH06128079A - Vertical type apparatus for liquid-phase epitaxial growth - Google Patents

Abstract

PURPOSE:To enable the prevention of a defective remaining liquid by preparing a strip from a material good in wettability with a raw material solution and installing the strip in contact with one end of an opening of each wafer housing dish so as to extend downward. CONSTITUTION:In this apparatus for the liquid-phase epitaxial growth equipped with a passage 6 for flowing down a raw material solution 4 in one end of a cassette 3 for laminating and housing wafer housing dishes 2 having an opening for discharging the raw material solution 4 in a part of a sidewall, the epitaxial growth is carried out as follows: That is, a strip 8 made of a material good in wettability with the raw material solution 4 is arranged in contact with one end of the opening of each wafer housing dish 2 so as to extend downward. The strip 8 good in the wettability with the raw material solution 4 can be arranged in the passage to rapidly remove the raw material solution 4 using the strip 8 as a guide. Thereby, the epitaxial growth can be completed in an early stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical liquid phase epitaxial growth apparatus, and more particularly to a vertical liquid phase epitaxial growth apparatus suitable for growing semiconductor epitaxial wafers such as GaAs, AlGaAs, InGaAsP used for light emitting diodes and the like.

[0002]

2. Description of the Related Art A vertical type liquid phase epitaxial growth apparatus for epitaxially growing a large number of wafers at the same time is disclosed in Japanese Patent Laid-Open Publication No.
No. 9-213699. FIG. 3 is a front sectional view of this apparatus, and FIG. 4 is a perspective view of the wafer storage tray used in FIG. The wafers 1 are stored in the storage tray 2, and the storage trays 2 are stacked in the cassette 3. A passage 6 for flowing the raw material solution 4 is provided in the cassette 3. The cassette 3 is placed on the collection container 7, and the raw material solution reservoir 5 is placed on the cassette 3. The raw material solution 4 fills the inside of the cassette 3 through the passage 6 from the bottom opening of the raw material solution reservoir 5 to grow an epitaxial layer on the wafer 1. After the growth, the raw material solution 4 is recovered in the recovery container 7 through the passage 6.

[0003]

In the conventional vertical liquid phase epitaxial growth apparatus, the raw material solution is discharged from the cassette in order to complete the epitaxial growth. At that time, the raw material solution remains on the surface of the wafer, so-called liquid residue. There is a problem that defects are likely to occur. 5 and 6 are views for explaining the liquid remaining defect, FIG. 5 is a plan view of the wafer storage tray, and FIG. 6 is a side sectional view. 5 and 6 (a)
As is clear from the above, the liquid residual defect 10 is likely to occur near the opening 9 of the wafer storage tray 2. Therefore, the present invention is intended to provide a vertical liquid phase epitaxial growth apparatus that can solve the above problems and prevent liquid remaining defects.

[0004]

The present invention has a wafer storage tray having a raw material solution discharge opening in a part of a side wall thereof, and a cassette for stacking and storing the wafer storage trays. In a liquid phase epitaxial growth apparatus having a passage for letting a raw material solution flow down at one end thereof, a material having good wettability with respect to the raw material solution, for example, a strip made of the same material as the growth substrate is provided in the opening of the wafer storage dish. The vertical liquid phase epitaxial growth apparatus is characterized in that it is arranged so as to contact one end and extend downward.

[0005]

FIG. 1 is a front sectional view of a vertical liquid phase epitaxial growth apparatus which is one embodiment of the present invention, and FIG. 2 shows an example of the positional relationship between the wafer storage tray and the strip used in FIG. FIG. In this device, a strip 8 is arranged in the passage 6 of the conventional device shown in FIG. 3, and one end of the strip 8 is held so as to be in contact with the opening of the wafer storage tray 2. This strip 8
It is made of a material having good wettability with respect to the raw material solution 4, for example, the same material as the wafer, a material contained in the raw material solution, or the like.

In this type of apparatus, a jig such as a wafer storage tray or a cassette is usually made of high-purity carbon which has poor wettability with respect to the raw material solution, but many wafers can be stored in the cassette. Therefore, the wafer storage tray tends to be shallow. As a result, the raw material solution does not wet the lower surface of the wafer storage dish, but since the wettability to the wafer is good and the wafer storage dish is shallow, the raw material solution 4 is not discharged to the passage as shown in FIG. 6A. Defective liquid residue occurs.

Therefore, in the present invention, by arranging the strip 8 having good wettability to the raw material solution 4 in the passage,
As shown in FIG. 6B, the raw material solution 4 can be promptly removed using the strip as a guide, and the epitaxial growth can be completed early. As a result, it has become possible to stably obtain a good epitaxial wafer having no liquid residue defect on the wafer surface. The arrangement of the strips is not limited to that shown in FIG. 2, and the strips may be slightly separated from the wafer storage tray. In short, it is sufficient that the raw material solution on the wafer surface is promptly removed.

[0008]

【Example】

(Example) Using the apparatus of FIG. 1, a diameter of 2 inches (50 m
m) Zn-doped (100) GaAs wafer on top of Zn
A doped AlGaAs epitaxial layer was grown. A strip cut from a GaAs substrate was placed in the passage in the cassette. The growth jigs such as the wafer storage tray and the cassette were made of high purity carbon. 10 wafers are set in the cassette, and G is stored in the raw material solution reservoir.
1000 g of a, 5050 mg of Al, 40 g of GaAs polycrystal, and 1000 mg of Zn as a dopant were added. Epitaxial growth is performed in a high purity hydrogen atmosphere at 90
After raising the temperature to 0 ° C., introducing the raw material solution into the cassette,
The temperature was lowered to 600 ° C. at a cooling rate of 0.1 to 1.0 ° C./min, and then the raw material solution was discharged into a recovery container. No residual liquid was found in the obtained wafer, and a wafer having a good epitaxial layer could be obtained. For comparison, when the epitaxial growth was performed in the same manner as the above except that the strips were removed from the apparatus of FIG. 1, five of the obtained wafers had defective liquid residue as shown in FIG.

[0009]

EFFECTS OF THE INVENTION According to the present invention, by adopting the above structure, the raw material solution after completion of growth can be discharged early through the strip having good wettability, and good epitaxial growth without liquid residual defect. The layers can now be grown.

[Brief description of drawings]

FIG. 1 is a front sectional view of a vertical liquid phase epitaxial growth apparatus which is one example of the present invention.

2 is a perspective view showing a positional relationship between a wafer storage tray and a strip in the apparatus of FIG.

FIG. 3 is a front sectional view of a conventional vertical liquid phase epitaxial growth apparatus.

FIG. 4 is a perspective view of a wafer storage tray used in the apparatus of FIG.

FIG. 5 is a plan view showing a liquid remaining defect on a wafer surface grown by a conventional apparatus.

FIG. 6 is a diagram for explaining the liquid remaining on the wafer surface in the conventional apparatus and the discharge state of the raw material solution in the apparatus of the present invention.

Claims (2)

[Claims] 1. A wafer storage tray having an opening for discharging a raw material solution on a part of a side wall thereof, and a cassette for stacking and storing the wafer storage trays. The raw material solution is flown down to one end of the cassette. In a liquid phase epitaxial growth apparatus having a passage, a strip made of a material having a good wettability with respect to a raw material solution is arranged in contact with one end of the opening of the wafer storage plate and extends downward. Vertical liquid phase epitaxial growth system. 2. The vertical liquid phase epitaxial growth apparatus according to claim 1, wherein a strip made of the same material as that of the growth substrate is used.