JPS6163590A - Installation for production of single cyrstal of compound semiconductor - Google Patents

Abstract

PURPOSE:The insulating part is made of a polytype AlN or a sintered AlN coated with polytype AlN and the part of increased heat insulation properties is used to enable the production of single crystals of large size and high quality. CONSTITUTION:The single cystal production unit is composed of a high-pressure vessel 1, crucible 2, crucible supporters 3, 4, 5, a heater surrounding coaxially the crucible 2, and a cylindrical insulator 12 arranged outside the heater 6. the insulator 12 is made of a polytype aluminum nitride or aluminum nitride coasted with polytype aluminum nitride and formed by following procedures. Namely, aluminum nitride, yttrium oxide and silicon dioxide are mixed, the mixture is formed using paraffin, the, the paraffin is removed and the formed product is heated at about 2,000 deg.C for 2 hours in a nitrogen atmosphere to give the objective insulation part of polytype aluminum nitride consisting of Al-Si-O-N compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus used for manufacturing compound semiconductor single crystals by the LEC method.

[Technical background of the invention and its problems] LE'C has been conventionally used as a method for manufacturing compound semiconductor single crystals such as GaAs, GaP, and InP, which have a high decomposition pressure at their melting point.
The law is known.

To explain this method using FIG. 1, first, a crucible 2 containing a crystal raw material and a sealant such as B203 is mounted on a crucible holder 3.4.5 disposed in a high-pressure container 1. .

Next, the crystal raw material and sealant in the crucible 2 are heated and melted by a heating element 6 coaxially surrounding the crucible 2.

At this time, the crystal raw material melt 7 and the sealant melt 8 are in a two-layer state due to the density difference, and the crystal raw material melt 7 has a large density (the density of the melt is about 5.7 ref/cffl for Ga AS, InP
about 5.0 (1/C11', GaP about 4°4ri/[i
) is a low-density sealant melt 8 (R liquid density is B2O3
1.59/c+/), the decomposition and evaporation of the crystal raw material melt 7 is suppressed, and by pressurizing the inside of the high-pressure container 1 with an inert gas, the vaporization of the crystal raw material melt 7 is suppressed. It will be done.

In this state, the seed crystal 1 attached to the tip of the crystal pulling shaft 9
0 is passed through the sealant melt 8 and brought into contact with the crystal raw material melt 7, and then pulled up while rotating the pulling shaft 9 to obtain the single crystal 11.

As described above, the LEC method has the advantage of being able to produce single crystals with relatively simple equipment, but the crystal growth is performed under high temperature and high pressure.
It has the disadvantage of large crystal defects due to heat dissipation due to heat convection and uneven temperature distribution.

For this reason, in order to maintain an appropriate temperature distribution within the crucible and ensure the heating efficiency of the heating element, heat is generated outside and above and below the heating element.
A heat retaining member 12 for shielding is provided.

This heat insulating member 12 and the crucible holder 3.4.5 include
Carbon products are usually used because they are easy to shape and lightweight.

However, carbon products are easily oxidized and deteriorated by atmospheric gases, traces of oxygen and water vapor in B203, or oxygen and water vapor contained in the carbon product itself due to adsorption, so the durability of carbon products decreases. Of course, there was a problem in that the oxidation reactants flew into the crucible being stirred by the high-pressure gas convection and contaminated the crystal Fjl'4.

The inventors of the present invention conducted research to solve these problems, and found that aluminum nitride sintered bodies were the most suitable material for the heat-retaining member, and filed an application for the same. This heat-retaining member made of sintered aluminum nitride has little oxidative deterioration, reduces contamination of the crystal raw material melt by oxidation products, and improves crystal quality. With the increasing demand for heat-retaining materials, there is a need for heat-retaining members with greater heat-retaining ability.

[Object of the invention] The present invention has been made to address these points.
□An object of the present invention is to provide an apparatus for manufacturing a compound semiconductor single crystal that can manufacture a larger, high-quality single crystal by using a heat-retaining member with a large heat-retaining ability.

C. Summary of the Invention] That is, the compound semiconductor crystal manufacturing apparatus of the present invention comprises a high-pressure container, a crucible and a crucible holder arranged in the high-pressure container, a heating element surrounding the crucible and the crucible holder, and a heating element surrounding the crucible and the crucible holder. In a compound semiconductor single crystal manufacturing apparatus mainly comprising a heat insulating member disposed outside a heating element and a crystal pulling device disposed on the crucible so as to be movable up and down,
The heat insulating member is characterized in that it is constituted by polytype aluminum nitride or an aluminum nitride sintered body coated with polytype aluminum nitride.

The heat insulating member made of polytype aluminum nitride in the present invention is manufactured, for example, as follows.

That is, first, 0.1 to 10 percent silicon dioxide and, if necessary, densification aids such as calcium oxide and yttrium oxide are added and mixed to aluminum nitride, and then a binder is added to form a specified cylinder or plate shape. After molding into a shape, it is degreased and heated to a temperature of 1700 to 200 in an inert gas such as a nitrogen atmosphere.
Heat at a high temperature of 0'C. When the sintering is completed in this way, 1q of heat insulating members made entirely of Aβ-Si-0-N-based compounds are completed.

Also, 7P with polytype aluminum nitride! A heat insulating material made of N-treated aluminum nitride is manufactured as follows.

That is, a film of silicon dioxide is formed on the surface of an aluminum nitride molded body or sintered body molded into the shape of a predetermined heat insulating material by a CVD method or a sputtering method, and in the case of a molded body, a film of 1700" is formed in a nitrogen atmosphere. It is heated to a temperature of 150° C. or higher to react and sinter, and in the case of a sintered body,
By heating above 0'C to cause a reaction, the surface becomes A
A heat insulating member made of an aluminum nitride sintered body coated with polytype aluminum nitride made of a Q-3i-0-N-based compound is obtained. Note that the thickness of the polytype aluminum nitride layer formed by this method depends on the thickness of the silicon dioxide film.

In addition, as polytype aluminum nitride, △e-
There is also a -N type, which can be applied almost in the same way as the Al-Si-0-N type.

In the present invention, a cylindrical heat insulating member made of an aluminum nitride sintered body whose outer periphery is coated with polytype aluminum nitride has excellent characteristics because there is no risk of contamination of the crystal raw material melt and it has excellent heat retention properties. Excellent semiconductor crystal 1
I can do it.

[Embodiments of the invention] Next, examples of the present invention will be described.

Embodiment 1 As shown in the drawings, the apparatus of the present invention includes a high-pressure container 1, a crucible 2 and a crucible pedestal 3.
5, a heating element 6 coaxially surrounding the crucible 2, and a cylindrical heat insulating member 12 disposed around the outer periphery of the heating element 6. The heat insulating member 12 is constructed as follows. Manufactured.

grain? J! 1.2μm aluminum nitride 931a%,
Yttrium oxide type 3 seedlings with particle size O17μm and particle size 0
．． 2μm of silicon dioxide is mixed with 2μm of silicon dioxide, and after adding a predetermined amount of paraffin and molding, it is degreased, reacted in a nitrogen atmosphere at about 2000'CX for 2 hours, and fired to reduce the whole to β. -81- A polytype aluminum nitride heat insulating member made of a N-based compound is used. This heat retaining member had a thermal conductivity that was about 1/10 lower than that of a member made of aluminum nitride, and had excellent heat retaining properties.

When a Qa AS single crystal was pulled by the conventional method using this apparatus, crystal defects were reduced compared to when an aluminum nitride heating member was used because the temperature distribution in the crucible was more uniform. Furthermore, compared to the case where conventional carbon products were used, crystal defects were reduced by 1/10g.

Example 2 Ga was heated using the same equipment as in Example 1, except that the heat insulating member in Example 1 was manufactured as follows.
An As single crystal was pulled up.

This heat insulating member is made by forming a silicon dioxide film with a thickness of 1 μm on the surface of a cylindrical aluminum nitride molded body as shown in Fig. 2 using the CVD method, and then in a nitrogen atmosphere for 20 minutes.
A heat insulating member consisting of an aluminum nitride sintered body 14 coated with a polytype aluminum nitride layer 13 was manufactured by reacting and firing under the conditions of 00° C. for 2 hours. The resulting single crystal had fewer crystal defects than when an aluminum nitride heat insulating member was used.

[Effect of the invention 1] As explained above, in the compound semiconductor single crystal manufacturing apparatus of the present invention, polytype aluminum nitride, which has better heat retention than ordinary aluminum nitride, is used for the heat insulation member, so that the inside of the crucible is As a result, the temperature distribution of
1 q of high-quality compound semiconductor single crystals can be obtained, and temperature distribution that occurs when the device is enlarged can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view schematically showing an embodiment of the apparatus of the present invention, and FIG. 2 is a perspective view showing an embodiment of a heat insulating member which is a characteristic part of the apparatus of the present invention. 1・・・・・・・・・・・・・・・High pressure container 2・・・・
・・・・・・・・・・・・ Crucible 3.4.5 Crucible holder 6・・・・・・・・・・・・Heating element 7・・・
......Crystal raw material melt 8...
......Sealant melt 12...
・・・・Heat insulation member 13・・・・・・・・・・・・・・・
aluminum nitride polytype layer

Claims (3)

[Claims] (1) a high-pressure container, a crucible and a crucible holder arranged in the high-pressure container, a heating element surrounding the crucible and the crucible holder, a heat-retaining member arranged outside the heating element; In a compound semiconductor single crystal manufacturing apparatus mainly consisting of a crystal pulling device disposed on a crucible so as to be able to move up and down, the heat insulating member is made of polytype aluminum nitride or aluminum nitride sintered coated with polytype aluminum nitride. An apparatus for manufacturing a compound semiconductor single crystal, characterized in that it is made up of solids. (2) Polytype aluminum nitride is Al-Si-
An apparatus for producing a compound semiconductor single crystal according to claim 1, which is made of an O-N compound. (3) The apparatus for manufacturing a compound semiconductor single crystal according to claim 2, wherein the Al-Si-O-N-based compound is obtained by heating aluminum nitride and silicon dioxide at a high temperature to cause a reaction.