JPH0633225B2 - Liquid phase epitaxial growth method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid phase epitaxial growth method, and more particularly to an epitaxial growth method using metal In, which becomes a solid at around room temperature, as a solvent.

[Prior Art] Liquid phase epitaxy, vapor phase epitaxy (VPE), metalorganic pyrolysis vapor phase epitaxy (MOCVD), molecular beam epitaxy (M) is used for epitaxial growth of compound semiconductors such as GaAs.
BE method), etc., but the liquid phase growth method is most suitable for obtaining a high quality crystal phase and is widely used at the production level of light emitting diodes and semiconductor lasers. The liquid phase growth method is a method of directly contacting a substrate with a solution containing a component element to grow crystals, and can be classified into various methods depending on how the substrate is brought into contact with the solution. Among them, the slide boat method as shown in FIG. 10 is generally used.

That is, the material holder 101 is slid to distribute the growth solution 103 in the growth solution reservoir 102 to the solution reservoir 105 of the solution holder 104, and then the substrate holder 106 is slid to grow the growth in the substrate 107 and the solution reservoir 105. A crystal layer is formed on the substrate 107 by bringing the crystal layer into contact therewith.

In this way, since the growth solution 103 is distributed to the thin solution reservoir 105 and then brought into contact with the substrate 107, the temperature distribution of the growth solution 103 at the time of contact can be easily made uniform, and as a result, the film thickness can be made uniform. An epitaxial layer can be grown. For example, in the liquid phase epitaxial method using metallic gallium such as GaAs or GaAlAs as a solvent, the variation in film thickness is ± 5.
% Or less, it is possible to perform growth with extremely excellent uniformity.

However, since metal In, which serves as a solvent when growing InP, InAs, etc., has a melting point of 156.4 ° C. and becomes a solid near room temperature, the growth ends when these compound semiconductors are grown by a slide boat. The growth solution remaining during the subsequent boat decomposition becomes solid, and it becomes difficult to remove it from the slide boat.

This slide boat is mainly composed of graphite, but it is necessary to use a thick boat so that it will not be damaged even if a force is applied in order to take out solid In after the growth is completed. You cannot use what you have done. That is, the growth solution distribution type slide boat shown in FIG. 10 cannot be used for the growth of InP, InAs, etc., and the substrate holder 10 as shown in FIG.
The slide boat having a simple structure in which the raw material holder 101 is arranged immediately above 6 has to be used.

As a result, it is difficult to grow an epitaxial layer having excellent film thickness uniformity with InP or InAs. For example, when an InP epitaxial layer having a thickness of 1 μm is grown, the film thickness varies ± 20 to 30%. Was there.

[Problems to be Solved by the Invention] As described above, in the liquid phase epitaxial method using the conventional slide boat, a uniform epitaxial layer using InP or InAs, which becomes a solid near room temperature as a solvent (In), is formed. There was a problem that it could not be grown with a uniform film thickness.

Thus, the object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a liquid phase epitaxial growth method capable of growing an epitaxial layer excellent in film thickness uniformity even when metal In, which is fixed at around room temperature, is used as a solvent. To do.

[Means for Solving Problems] In order to achieve the above-mentioned object, the liquid phase epitaxial growth method of the present invention involves contacting a substrate with a growth solution using metal In, which becomes solid at room temperature, as a solvent by the slide boat method. Is performed to perform epitaxial growth, and then metallic Ga is added to the growth solution remaining in the solution pool.

[Function] Since metallic Ga has a melting point of 29.78 ° C., which is extremely low as a metal, by adding metallic Ga to the residual growth solution after completion of growth, the growth solution becomes a liquid phase at around room temperature. You can Therefore, it becomes possible to perform epitaxial growth using In as a solvent, for example, using a growth solution distribution type slide boat as shown in FIG.

In FIG. 1, the substrate 1 is accommodated in the substrate holder 2, the growth solution 3 is accommodated in the raw material holder 4, and the metal Ga 5 is accommodated in the Ga holder 6, respectively. After being distributed in the solution reservoir 8 of the solution holder 7, the substrate holder 2 is slid to grow epitaxially on the substrate 1. After the growth is completed, the shutter 9 and the raw material holder 4 are slid together to add the metallic Ga 5 to the growth solution 3 remaining in the raw material holder 4 and the solution holder 7.

In this way, epitaxial growth with a uniform film thickness is performed, and metal Ga is added to the growth solution.

EXAMPLES Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a cross-sectional configuration diagram of a slide boat used in the liquid phase epitaxial growth method according to one embodiment of the present invention. The substrate holder 11 has a 2-inch (about 5.1 cm) size I
The nP substrate 12 is held, and the raw material solution reservoir 1 of the raw material holder 13 is held.
In, 100 g of In and 1.5 g of InP crystal are stored in the No. 4, and In100 g is stored in the meltback raw material solution reservoir 15.
Moreover, 100 Ga of metal Ga is accommodated in each of the two Ga melt reservoirs 17 and 18 of the Ga holder 16 located at the top. A solution holder 2 having a thickness of 3 mm, which has two solution reservoirs 19 and 20 between the substrate holder 11 and the raw material holder 13.
1, a shutter 22 having two openings is interposed between the raw material holder 13 and the Ga holder 16.

Place this slide boat in a reaction tube (not shown),
After replacing the inside of the reaction tube with hydrogen gas, the temperature was raised to 660 ° C. by an external heating furnace (not shown). Furnace temperature is 660
After 2 hours have passed since the temperature reached to 0 ° C., the raw material holder 13 is slid so that the growth solution and the meltback solution stored in the raw material solution reservoir 14 and the meltback raw material solution reservoir 15 are respectively stored in the solution holder 21. It is distributed into the reservoirs 19 and 20 (see FIG. 3), and then the raw material holder 13 is returned to its original position (see FIG. 4).

Next, the inside of the furnace is cooled at a cooling rate of 0.5 ° C./min, and 12 minutes after the start of the temperature decrease, that is, when the temperature inside the furnace reaches 654 ° C., the substrate holder 11 is slid to move the substrate 12 to the solution in the solution holder 21. The meltback solution was brought into contact with the substrate 12 for about 5 seconds while being positioned directly below the reservoir 20. After the melt-back is performed in this way to remove the heat-deteriorated layer on the surface of the substrate 12, the substrate holder 11 is slid again to position the substrate 12 directly below the solution reservoir 19 of the solution holder 21, and the substrate 12 is kept for 20 minutes. Was contacted with the growth solution (see FIG. 5). As a result, InP on the substrate 12
Epitaxial layers are grown.

After that, the substrate holder 11 was returned to the original position to perform melt-off (see FIG. 6). Further, the shutter 22 and the raw material holder 13 are slid together and the growth solution and the meltback solution remaining in the solution reservoirs 19 and 20 of the solution holder 21, the raw material solution reservoir 14 of the raw material holder 13 and the meltback raw material. The respective solutions were mixed in the solution reservoir 15 and the metallic Ga contained in the Ga melt reservoirs 17 and 18 of the Ga holder 16 was added to these solutions (see FIG. 7).

In this state, the inside of the furnace was cooled, and when the temperature inside the furnace was around room temperature, the slide boat was taken out from the reaction tube and disassembled. At this time, the growth solution and the meltback solution using In as a solvent kept the liquid state because the metallic Ga was added, and the boat could be easily cleaned.

Further, when the film thickness of the InP epitaxial layer grown on the substrate 12 was measured, the average was 3.8 μm, and the variation was ± 5% or less.

Although the metal Ga is positioned at the top of the slide boat, that is, at the top of the growth solution in the above embodiment, the present invention is not limited to this. It is sufficient that the metal Ga in the growth solution can be added after the growth is completed. Therefore, for example, as shown in FIG. 8, the raw material holder 31 and the solution holder 32 are provided with Ga melt reservoirs 33 and 34 to accommodate metallic Ga, and after the growth is completed, the raw material holder 31 is slid to move the same as shown in FIG. The metallic Ga may be added to the remaining growth solution.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects are exhibited.

(1) After the growth is completed, by adding metallic Ga to the remaining growth solution, the remaining growth solution can be taken out in the liquid state even in the liquid phase epitaxial method using metal In as a solvent that becomes a solid at room temperature as a solvent. Is possible. Therefore, it has become possible to use a slide boat made of finely worked or thin plate material.

(2) As a result, it became possible to grow an epitaxial layer with excellent film thickness uniformity even by a liquid phase epitaxial method using In as a solvent.

[Brief description of drawings]

FIG. 1 is a block diagram of a slide boat that can be used in the liquid phase epitaxial growth method of the present invention, FIGS. 2 to 7 are process drawings showing the method according to one embodiment of the present invention, and FIG.
FIG. 9 and FIG. 9 are process drawings showing another embodiment, respectively.
FIG. 0 and FIG. 11 are configuration diagrams of slide boats used in the conventional example. In the figure, 1 is a substrate, 2 is a substrate holder, 3 is a growth solution, 5
Is metal Ga, 7 is a solution holder, and 8 is a solution reservoir.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiichiro Konno 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable, Ltd. Electric Wire Laboratory (72) Inventor Hiroshi Sugimoto 5-chome, Hidaka-cho, Hitachi-shi, Ibaraki 1-1 Electric Cable Research Institute, Hitachi Cable (72) Inventor Shoji Kuma 5-1-1 Hidakacho, Hitachi City, Ibaraki Hitachi Cable Research Laboratory, Hitachi Cable

Claims (1)

[Claims] 1. A substrate containing a growth solution containing metal In as a solvent in a solution reservoir of the solution holder and holding the substrate on the substrate holder, and sliding the solution holder and the substrate holder relative to each other. And the growth solution are brought into contact with each other for epitaxial growth, and then metallic Ga is added to the growth solution remaining in the solution reservoir.