JPS62106619A - Liquid epitaxial growing process - Google Patents

Abstract

PURPOSE:To perform the titled epitaxial growing process while protecting the epitaxial layer forming material by a method wherein source frames with openings in the central positions are provided along inner walls of solution reservoirs. CONSTITUTION:Solution reservoirs 14 provided with source frames 17 are filled with specified amount of weighed Ga while an epitaxial growing jig comprising a fixed member 13 with a GaAs substrate 11 arranged on a cavity 12 of the fixed member 13 and a slide member 15 is led in a reaction tube and then the epitaxial growing jig is heated up at a specified temperature using a heating furnace provided around the reaction tube to melt Ga in the solution reservoirs 14 at controlled heating temperature so that the constituent GaAs in the source frames 17 may be melted in the Ga in melted solution up to the saturated amount corresponding to the temperature of melted Ga. In such a state, while further lowering the temperature in the heating furnace, the slide member 15 is shifted in the arrow A direction to coat the substrate 11 with the Ga containing the melted GaAs in the solution reservoirs 14 for epitaxial growing process.

Description

[Detailed Description of the Invention] [Summary] This is an improved liquid phase epitaxial growth method for compound semiconductors such as gallium arsenide (GaAs), which can eliminate the phenomenon of edge growth in which an epitaxial layer is abnormally grown around the substrate on which it is grown. A liquid phase epitaxial growth method.

[Industrial application field]

The present invention relates to a method for liquid phase epitaxial growth of compound semiconductors such as GaAs.

When growing compound semiconductor crystals such as GaAs,
A fixing member made of carbon having a rectangular parallelepiped shape and having a concave portion in which a compound semiconductor substrate is placed, and a liquid solution that slides on the fixing member and fills it with a solution of an epitaxial layer forming material to be formed on the substrate. A rectangular parallelepiped-shaped slide member having a reservoir is prepared. Then, an epitaxial growth jig consisting of this fixing member and a slide member is installed in the reaction tube, and by heating this epitaxial growth jig, the epitaxial growth material in the liquid reservoir is melted, and this liquid reservoir is transferred onto the substrate. Slide and move
A liquid phase epitaxial growth method using a boat slide method is used in which an epitaxial layer is formed on a substrate by lowering the temperature of a heating furnace.

This method can be performed using simpler equipment than the vapor phase epitaxial growth method, has fewer crystal defects in the grown epitaxial crystal, and has a high crystal growth rate, so it is suitable for use in semiconductor laser devices and light emitting devices. It is often used to grow compound semiconductor crystals for materials such as diodes.

In such a liquid phase epitaxial growth method, the phenomenon of edge growth, in which the epitaxial layer grows abnormally around the substrate on which the epitaxial layer is to be formed, tends to occur, and there is a need for a liquid phase epitaxial growth method that can eliminate this phenomenon. There is.

[Conventional technology]

Regarding such a conventional method of liquid phase epitaxial growth, the cross-sectional view shown in FIG. 3, FIG. 4 which is a plan view showing the main part of FIG. 3, and FIG. This will be explained using figures.

As shown in FIGS. 3 to 5, a recess 2 is provided in a rectangular parallelepiped-shaped fixing member 1 made of carbon, and a compound semiconductor substrate 3 such as GaAs is placed in the recess 2. As shown in FIGS. On the other hand, this fixing member l
A slide member 5 made of carbon and having a rectangular parallelepiped shape is provided, which slides on the top in the direction of arrow A and has a liquid reservoir 4 in the form of a through hole in the shape of a rectangular parallelepiped.

Four crystal plates 6A, 6B, 6C, and 6D made of plate-shaped GaAs are installed along the inner wall of this liquid reservoir 4, and surrounded by these four crystal plates 6A, 6B, 6C, and 6D. The inside is filled with gallium (Ga) 7.

A liquid phase epitaxial growth jig consisting of the fixing member 1 and the slide member 5 is introduced into a reaction tube (not shown) made of quartz or the like, and the inside of the reaction tube 8 is made into an atmosphere of hydrogen gas. In this state, the epitaxial growth jig is heated to a temperature of approximately 900°C using a heating furnace (not shown) provided around the reaction tube, thereby filling the inside of the liquid reservoir 4 of the jig. Melt the Ga7.

By adjusting the melting temperature of this molten Ga, GaAs is transferred from the GaAs crystal plates 68, 6B, 6C, and 6D provided along the inner wall of the liquid reservoir 4 to the molten Ga.
A source of GaAs to be epitaxially grown on the substrate 3 is formed by melting GaAs into the molten Ga.

Next, the temperature of the heating furnace is lowered from 900° C. by a predetermined temperature gradient, and when the predetermined temperature is reached, the slide member 5 is moved along the direction of arrow A, so that the liquid reservoir 4 is positioned on the substrate 3. , place Ga in which GaAs is molten in a saturated state on the substrate 3, further lower the temperature of the heating furnace to a predetermined temperature, and grow GaAs on the substrate 3 by liquid phase epitaxial growth at this lowered epitaxial growth temperature. There is.

The GaAs crystal plates 68, 6B, 6G, and 6D thus installed along the inner wall of the through hole 4 serve to supply the GaAs component into the molten Ga, and at the same time serve to supply the GaAs component into the molten Ga. The liquid reservoir 4 having inside the substrate 3
When placed on top, it serves to cover the peripheral edge of the substrate 3, and thereby also serves to eliminate the phenomenon of edge growth that occurs abnormally on the peripheral edge of the substrate 3.

[Problem that the invention seeks to solve]

However, in the above method, the GaAs crystal plates 6A, 6B
.

It is necessary to process and finish 6C and 6D to highly accurate dimensions, and it is also necessary to process the internal dimensions of the liquid reservoir to be highly accurate.

Further, the crystal plates 6A, 6B, 6C, and 6D described above are placed in the liquid reservoir 4.
The installation work along the inner wall is complicated. Furthermore, even if it takes a long time to install this crystal plate inside the liquid reservoir 4, if the crystal plate falls down due to fluctuations of the solution in the liquid reservoir during crystal growth, the epitaxial growth operation may be interrupted. .

In addition, each time the crystal plate 6 undergoes repeated epitaxial growth,
Since A, 68.6C, and 6D are melted, their dimensions do not precisely match the inner wall of the through hole 4, so they are currently discarded every time they are grown, which increases the cost of epitaxial growth. However, the disadvantage is that the epitaxially grown substrate formed is expensive.

[Means for solving problems]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid phase epitaxial growth method that eliminates the above-mentioned drawbacks, allows the above-described crystal plate to be used for multiple epitaxial growths, and can be easily installed on the inner wall of a through hole.

In the liquid phase epitaxial growth method of the present invention, as shown in FIG. The source frame 17 protects the epitaxial layer forming material in the liquid reservoir 14 while epitaxial growth is performed.

[Effect]

In the liquid phase epitaxial growth method of the present invention, a frame-shaped source frame 17 made of the same material as the substrate 11 is installed in the liquid reservoir 14, and by using this frame-shaped source frame 17, the slide member 15 is It is not necessary to strictly process the dimensions of the liquid reservoir 14 to be provided, and the work of installing the source frame 17 in the liquid reservoir 14 is facilitated.
By using No. 7, it can be used for multiple epitaxial growths, and a low-cost epitaxial growth substrate can be obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an apparatus used in the liquid phase epitaxial growth method of the present invention, and FIG. 2 is a plan view showing the main parts of FIG. 1.

As shown in FIGS. 1 and 2, the epitaxial growth jig used in the method of the present invention has a recess 12 in which a compound semiconductor substrate 11 such as GaAs is placed, a rectangular parallelepiped-shaped fixing member 13 made of carbon, It slides on the fixing member 13 in the six directions of arrows, has a through-hole-shaped liquid reservoir 14 filled with the epitaxial layer forming material to be formed on the substrate 11, and is made of rectangular parallelepiped carbon. It consists of a slide member 15.

Furthermore, as shown in FIG. 2, the epitaxial growth jig used in the method of the present invention has an opening 16 in the center along the inner wall of the liquid reservoir 14, and is made of the same material as the substrate 11. A frame-shaped source frame 17 is installed. This source frame 17 is formed by cutting the center part of a GaAs crystal plate with a thickness of about 21 m using an ultrasonic cutter.

G(
1 is weighed and filled in a predetermined amount, and with the GaAs substrate 11 installed in the recess 12 of the fixing member 13, an epitaxial growth jig consisting of the fixing member 13 and the slide member 15 is placed in a reaction tube (not shown). ), the epitaxial growth jig is heated to a predetermined temperature using a heating furnace (not shown) provided around the reaction tube, and the Ga in the liquid reservoir 14 is heated.
is melted, and the heating temperature is adjusted to melt the GaAs component of the source frame 17 into the solution of Ga in an amount corresponding to the temperature of the Ga.

In this state, the slide member 15 is moved along the direction of arrow A while further lowering the temperature of the heating furnace, and the liquid reservoir 14 is installed on the substrate 11. molten GaAs is deposited and epitaxial growth is performed.

In this way, the peripheral edge of the base Fj, 11 will have Ga
Since the As source frame 17 is installed, the substrate 110
The phenomenon of edge growth, in which GaAs crystals abnormally grow epitaxially on the periphery, is prevented.

Furthermore, if the used source frame 17 is etched using hydrochloric acid (Hα), Ga attached around it can be easily etched.
The Ga component of As can be removed, and this source frame 17 can be used for several epitaxial growths.

Furthermore, since the source frame 17 is not in the form of a crystal plate as in the conventional case but in the form of a frame, it can be easily installed in the liquid reservoir.
It is not necessary to process the source frame with precision and the internal dimensions of the liquid reservoir 14 as strictly as in the past.

Further, during epitaxial growth, the source frame does not collapse due to fluctuations of the solution in the liquid reservoir, and stable epitaxial growth can be performed.

Furthermore, although the above embodiments have been explained using an example in which a GaAs epitaxial layer is formed on a GaAs substrate, the present invention is also applicable to heteroepitaxial growth in which a compound semiconductor such as GaAsAl is formed on a GaAs substrate. It is a thermal theory that can be applied and further applied to the case where these epitaxial layers are formed in a multilayer structure on a GaAs substrate.

〔Effect of the invention〕

As described above, according to the epitaxial growth method of the present invention, it is not necessary to form the liquid reservoir of the slide member with high precision as in the conventional method.

Moreover, since the source frame is used for several epitaxial growths, it is economical.

In addition, since the source frame is installed along the inner wall of the liquid reservoir compared to the case where a conventional crystal plate is used, molten epitaxial growth material may enter the gap between the source frame and the inner wall of the liquid reservoir. The phenomenon in which the crystallinity of the epitaxial layer deteriorates can be avoided.

Furthermore, since components in the liquid reservoir adhering to the source frame can be easily removed by etching, the source frame can be kept clean and epitaxial growth with good crystallinity can be achieved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an epitaxial growth jig used in the liquid phase epitaxial growth method of the present invention, Figure 2 is a perspective view showing the main parts of Figure 1, and Figure 3 is an epitaxial growth jig used in the conventional liquid phase epitaxial growth method. A sectional view of the jig, FIG. 4 is a plan view showing the main part of FIG. 3, and FIG. 5 is a sectional view showing the main part of FIG. 3. In the figure, 11 is a substrate, 12 is a recess, 13 is a fixing member, 14 is a liquid reservoir, 15 is a slide member, 16 is an opening, and 17 is a source frame. Figure 1 Figure 2 Figure e/1 direction, -, rfI＼ Shinji odor f direction Figure 3

Claims (1)

[Claims] A fixing member (13) on which the substrate (11) is installed, and a solution-form epitaxial layer forming material that slides on the fixing member (13) and is to be grown on the substrate (11). a slide member (15) having a liquid reservoir (14) for accommodating the liquid reservoir (14), the method for forming an epitaxial layer on the substrate (11) by installing the liquid reservoir (14) on the substrate (11). , A frame-shaped source frame (17) made of the same material as the substrate (11) and having an opening (16) in the center is installed along the inner wall of the liquid reservoir (14), and the source frame ( 17) A liquid phase epitaxial growth method characterized in that epitaxial growth is performed while protecting the epitaxial layer forming material in the liquid reservoir (14).