JPS6287478A - Equipment for production ga-as single crystal - Google Patents

Abstract

PURPOSE:A quartz boat is formed in a vessel with the opening at its top and Ga is placed in it, then a support 4 is laid over the boat between both edges whereby the reproducibility of the form of GaAs single crystals is improved and the quartz boat can be reused. CONSTITUTION:Ga and the seed crystal are placed in the quartz ampoule on one side end, while As is on the other side end, then the ampoule is vacuumed and sealed. The resultant ampoule is placed in a two-unit electric oven consisting of the low-temperature unit and the high-temperature unit. Then, the low-temperature unit is kept at about 600 deg.C to maintain the vapor pressure of As at 1 atmospheric pressure in the ampoule and the high-temperature unit is kept near 1,200 deg.C to effect the synthesis of GaAs. Then, the temperature is further raised to keep the seed crystal at 1,238 deg.C and to adjust the temperature ingredient of the GaAs melt to 0.5 deg.C/cm to effect seeding. Then, the ampoule is cooled down to solidify the whole part, further down to room temperature to obtain GaAs single crystal. The quartz boat 2 is equipped with a support 4 which rides over boat walls and is made of a not-softening material even at high temperature to prevent the boat 2 from deforming with heat.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gallium arsenide (hereinafter referred to as Qa AS) single crystal production apparatus, and particularly relates to a Qa ASS by boat method.
This paper relates to improvements in unit manufacturing equipment.

[Conventional technology j Conventionally, in the production of Qa AS single crystals by the horizontal boat method, gallium (Ga
) was loaded and placed in an ampoule, and arsenic (As) was put into the other end of the ampoule, and Qa AS was synthesized and a single crystal was grown in a vacuum-sealed quartz ampoule made of quartz glass.

A specific conventional example will be explained using FIG. FIG. 3 is a cross-sectional view of the inside of a quartz ampoule in a conventional gallium arsenide single crystal manufacturing apparatus, in which 1 is a quartz ampoule, 2 is a quartz boat, and 3 is a Qa AS crystal.

First, 2000 g of Ga and a seed crystal are placed in a quartz boat 2, placed on one end of the quartz ampoule 1, and A
32,200 g was put therein, and after vacuuming for 1 hour under reduced pressure of 5x 10 T Qrr or less, it was sealed. The completed quartz ampoule 1 is inserted into a double electric furnace (not shown) consisting of a low temperature furnace and a high temperature furnace.

Next, keep the low-temperature furnace at about 600°C and
The vapor pressure of s is maintained at i atm, and in the high temperature furnace, 120
After carrying out the GaAS synthesis reaction at around 0°C, the temperature is further increased to adjust the seed crystal portion to 1238°C and the humidity gradient in the QaAs melt to 0.5°C/cm to perform seeding. Thereafter, it was cooled at a rate of about 1.0° C./hour to solidify the whole in 50 hours, and further cooled to room temperature at a rate of 100° C./hour.

In this way, a Qa As with a width of 5 cm and a length of 40 cm is made.
Single crystal 41500 was produced.

[Problems to be Solved by the Invention] Since the melting point of Qa AS is approximately 1238°C, it is necessary to seed at a high temperature of 1238°C or higher as described above. However, the boat 2 on which the Qa As is placed is generally made of quartz, and this quartz softens when the temperature exceeds about 1200°C. Therefore, the quartz boat 2 undergoes thermal deformation during heating in the high-temperature furnace, and as a result, the G
The reproducibility of the shape of the aAs single crystal was significantly degraded. Furthermore, since the quartz boat 2 is deformed, it is difficult to reuse it, and the life of the boat is short.

[Object of the invention] The object of the present invention is to solve the problems of the prior art described above,
An object of the present invention is to provide a gallium arsenide single crystal manufacturing apparatus that can prevent thermal deformation of a quartz boat, improve reproducibility of the shape of a QaAs single crystal, and reuse the quartz boat.

[Summary of the Invention] In order to achieve the above object, the present invention forms a quartz boat in the shape of a container with an open top for placing and storing gallium, and a support member made of a high temperature stable material is inserted into the opening of the quartz boat. It is installed across the upper edge of the boat to prevent thermal deformation of the quartz boat.

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

FIG. 1 is a cross-sectional view of the inside of a quartz ampoule in a gallium arsenide single crystal production apparatus according to an embodiment of the present invention. In the figure,
1 is a quartz ampoule, and 2 is a quartz boat with an open top for placing gallium.

A support member 4 made of alumina-silica ceramics is installed so as to span between the upper edges of the opening along the longitudinal direction of the quartz boat 2. Both ends of the support member 4 are bent at right angles to form engagement pieces 4a, which engage the outside of the upper edge of the opening of the quartz boat 2. FIG. 2 is a plan view of the quartz boat 2 on which the support member 4 is installed.

That is, the apparatus of this embodiment is different from the conventional example shown in FIG. 3 in that the quartz boat 2 is provided with a support member 4 that does not soften even when heated to high temperatures, thereby preventing the quartz boat 2 from being thermally deformed.

Using the apparatus having such a configuration, the same amount of GaAs single crystal 3 was produced in exactly the same manner as in the conventional example shown in FIG.

Thereafter, when the quartz boat 2 was examined, no thermal deformation was observed, and high reproducibility in the shape of the QaAs single crystal 3 was obtained. In addition, as a result of measuring the electrical properties of the produced GaAs single crystal 3, it was found that the properties were similar to those of the QaAs single crystal obtained in the conventional example, and even when the support member 4 was used, a single crystal with excellent properties was produced. I found out that it can be done.

In addition to alumina-silica ceramics, the support member 4 is made of silicon carbide, silicon nitride, silicon oxide, boron nitride,
It may also be composed of carbon, alumina oxide, or the like.

Further, in the above embodiment, the shape of the support member 4 is a plate shape as shown in FIGS. 1 and 2, but the shape is not limited to this. good. Furthermore, when using a long quartz boat,
If a plurality of supporting members are spanned over the quartz boat at predetermined intervals, the effect will be more effective.

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

(1) Since the support member made of a high-temperature stable material is installed across the upper edge of the opening of the quartz boat, thermal deformation of the quartz boat during heating in a high-temperature furnace can be prevented.

(2) Therefore, the reproducibility of the shape of the produced GaAs single crystal is improved.

[3] Furthermore, since the quartz boat does not deform, the quartz boat can be easily reused, and the life of the quartz boat can be extended.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the inside of a quartz ampoule in a gallium arsenide single crystal production apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of a quartz boat with a supporting member installed, and FIG. FIG. 3 is a cross-sectional view inside the ampoule. In the figure, 1 is a quartz ampoule, 2 is a quartz boat, and 3 is a Ga
As single crystal, 4 is a support member, and 4a is an engagement piece.

Claims (4)

[Claims] (1) By forming a vacuum-sealed quartz ampoule with a quartz boat containing gallium placed on one end and arsenic placed on the other end, and heating the quartz ampoule. In the apparatus in which gallium arsenide is synthesized and single crystals are grown in the quartz ampoule, the quartz boat is formed into a container shape with an open top for placing and accommodating the gallium, and an upper edge of the opening of the quartz boat is formed. A gallium arsenide single crystal production apparatus characterized in that a supporting member for preventing thermal deformation of the quartz boat is installed across the opening thereof. (2) The apparatus for producing gallium arsenide single crystals according to claim 1, wherein the supporting member is made of a high temperature stable material such as alumina-silica ceramics or silicon carbide. (3) The gallium arsenide according to claim 1 or 2, characterized in that the support member has engagement pieces at both ends thereof that engage while covering the outside from the upper edge of the opening. Single crystal production equipment. (4) The opening of the quartz boat is formed into a substantially rectangular or elliptical cross section, and the supporting member is stretched across the upper edge along the longitudinal direction of the opening. An apparatus for producing a gallium arsenide single crystal according to any one of claims 1 to 3.