JPS61136987A - Vessel for growing single crystal - Google Patents

Abstract

PURPOSE:To dispense with a special surface treatment of a vessel by spreading a cloth-like member of a material which does not react with a semiconductor single crystal and the material of the vessel to cover the inner wall of the vessel in the vessel for growing a compd. semiconductor by a boat method, etc. CONSTITUTION:A cloth-like member 3 (e.g., quartz fiber cloth) formed by a material which does not react with a semiconductor single crystal and the material of a growth vessel 2 is spread in the vessel 2 (e.g., a quartz boat) for growing a single crystal capable of maintaining thermal and mechanical strength during the growing of a compd. semiconductor single crystal to cover the inner wall of the vessel 2. A seed crystal and a raw material 4 are then charged into the growth vessel 2, and arranged in a quartz ampule 1. The inside of the ampule 1 is made to vacuum, and the raw material 4 is heated and melted to grow a single crystal. Consequently, the pretreatment for forming an alpha-cristobalite layer on the inner surface of the growth vessel 2 can be dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background and Objectives of the Invention] The present invention relates to a single crystal growth vessel for growing compound semiconductors by a boat method or the like.

A conventional single crystal growth vessel is replaced by a Ga
This will be explained by taking As single crystal growth as an example. Purity for a GaAS single crystal growth vessel (boat).

Quartz glass is used because of its thermal conductivity.

However, if a boat is simply made of quartz glass, the crystal or boat will break due to the difference in thermal expansion coefficient due to close contact with QaAs, so after sandblasting the surface, heat treatment with Ga etc. is performed to form an α-cristobalite layer on the inner wall. The method is to use it after refining it. However, the surface treatment work for this boat is troublesome, and it is known that if the treatment is insufficient or if trace amounts of oxygen are mixed in during the production of quartz ampoules, it may become "wet" (adhesion). technique is required.

The present invention was made in view of the above situation, and an object of the present invention is to provide a single crystal growth container that does not require special surface treatment of the container.

[Summary of the Invention] The single crystal growth container of the present invention grows a single crystal of a compound semiconductor from a raw material in a container placed in a quartz ampoule, and the raw material is stored inside to grow the semiconductor single crystal. The container is formed of a material that does not react with the semiconductor single crystal and the material of the container, and is configured to cover the inner wall of the container. A cloth-like member laid inside the container is provided. That is, by arranging, for example, a cloth-like member such as a glass cloth on the inner wall of a quartz boat, which is made of fibers of GaAs and a substance that does not react with the boat, special surface treatment of the container is not required.

[Example] Hereinafter, the single crystal growth container of the present invention will be explained using examples and drawings. The figure is a sectional view. In the figure, 1 is a quartz ampoule, 2 is a quartz boat, 3 is a quartz fiber, and 4 is a Ga
It is an As crystal. A quartz fiber cloth 3, which is a cloth-like member that does not react with the GaAs crystal 4 and the quartz boat 2, is laid on the inner wall of the quartz boat 2 which is not subjected to any special pretreatment as in the prior art. Seed crystal and raw material Ga8 in quartz boat 2
Put 00g into one end of quartz ampoule 1, and put A into the other end.
S890 (after adding + and welding, 1 x 10-8 Tor
Evacuate and seal for at least 1 hour at a temperature below r.

Next, the quartz ampoule 1 is placed in a double-barreled electric furnace, and the temperature of the quartz boat 2 side (high temperature side) is raised to 1200° C. or higher, and the As side (low temperature furnace) is heated to 610° C. to cause a reaction. Imitating the completion of the GaAS synthesis reaction, the temperature of the high-temperature furnace was gradually raised while keeping the temperature of the low-temperature furnace constant, and the seeded part was heated to 12% of the GaAs melting point.
The temperature gradient was adjusted to 1.0 dra/ra so that the temperature on the quartz board 2 body side became even higher at 38°C. After dissolving a part of the seed crystal in this way, the single crystal is cooled to room temperature at a rate of about 1.0 deg/Hr while keeping the temperature gradient constant, and the single crystal is taken out. By the above method, the weight is about 16
A GaAs single crystal of 00(I) was obtained.

When the single crystal was taken out from the quartz boat 2, Ga A
It became clear that the s-crystal 4 and the quartz boat 2 were not in close contact at all. Then, the quartz fiber cloth 3 broke apart and remained inside the GaAs crystal 4 and the quartz boat 2. This GaAs crystal was sliced along the (100) plane, etched with molten KOH, and the dislocation density was measured. As a result, no slip dislocations due to stress with the boat wall were observed. It was found that both the front end and the rear end of the single crystal were low dislocation density crystals with a dislocation density of 200oc114 or less.

In this way, the single crystal growth container of this example has a cloth-like member made of a substance that does not chemically react with either the quartz boat or the Ga AS crystal. There is no direct contact between the GaAs crystal and the quartz boat, and the presence of the cloth-like material can alleviate the stress caused by the difference in thermal contraction rate after crystal solidification, and can prevent destruction of the GaAs crystal or quartz boat. Further, it is no longer necessary to perform special surface treatment of the quartz boat of the container, that is, to make the surface an α-cristobalite layer.

Therefore, the number of work steps can be reduced.

In the above embodiments, quartz glass was used as the boat material for GaAs crystal growth by the boat method, but materials other than quartz glass may also be used. Note that the present invention can be applied to all Boat methods and Bridgman methods. The cloth-like member laid inside the container may be not only a cloth made of quartz fibers but also any material as long as it does not react with the single crystal and does not come into close contact with the quartz boat.

[Effects of the Invention] As described above, the single crystal growth apparatus of the present invention also has the effect of eliminating the need for special surface treatment of the inner surface of the container and reducing the number of work steps.

[Brief explanation of the drawing]

The figure is a sectional view of an embodiment of the single crystal growth apparatus of the present invention. 1: Quartz ampoule, 2: Quartz boat, 3: Quartz fiber cloth, 4: GaAs crystal.

Claims (2)

[Claims] (1) In a device that grows a single crystal of a compound semiconductor from raw materials in a container placed in a quartz ampoule, the thermal and mechanical strength of the state in which the raw materials are stored inside and the semiconductor single crystal is grown is determined. The container is formed to be maintainable, and the fabric member is made of a material that does not react with the semiconductor single crystal and the material of the container and is laid in the container so as to cover the inner wall of the container. A single crystal growth container characterized by being provided with. (2) The single crystal growth container according to claim 1, wherein the container is formed of a quartz boat, and the cloth-like member is formed of a quartz fiber cloth.