JPS61132597A - Apparatus for producing compound semiconductor single crystal - Google Patents

Abstract

PURPOSE:To produce a semiconductor single crystal having high quality and low contamination with carbon and other impurities, in high reproducibility, by using specific multi-walled tube made of AlN as a heat-insulation cylinder of an apparatus for the production of a single crystal by LEC process, and growing a compound semiconductor single crystal with the apparatus. CONSTITUTION:A heat-insulation cylinder 20 is placed in the pressure vessel 11 (e.g. made of stainless steel) of an apparatus for the production of a compound semiconductor single crystal by LEC process. The cylinder 20 is free of carbonaceous materials and is composed of two cylinders 20a and 20b made of sintered AlN and a granular filler 20c made of sintered alN and having a size of 3-10mm. The GaAs raw material 14 and the B2Oj3 encapsulation material 15 are charged in the crucible 12 made of e.g. PBN, the space in the vessel 11 is pressurized with Ar gas, the crucible 12 is heated with the heater 17 to melt the raw material 14 and the encapsulation material 15, the seed crystal 22 is made to contact with the molten raw material 14 via the encapsulation material 15, and is pulled up to effect the growth of the single crystal 23. A semiconductor single crystal 23 having extremely decreased carbon contamination can be produced by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a compound semiconductor single crystal manufacturing apparatus for pulling and manufacturing a compound semiconductor single crystal using the LEC method (liquid capsule pulling method).

[Technical background of the invention and its problems]

In recent years, the LEC method has attracted attention as a method for producing compound semiconductor single crystals that have a high decomposition pressure at the melting point.

This LEC method is a method in which a single crystal is pulled with a liquid capsule material formed on a raw material melt, and is carried out in a single crystal manufacturing apparatus as shown in FIG. That is, a crucible 12 is placed in a pressurized container 11 via a crucible receiver 13, and a liquid used for the purpose of suppressing the decomposition of volatile components from the surface of the raw material and raw material melt of the crystal to be obtained is placed in the crucible 12. Add 15 pieces of capsule material (820!L). Then,
After a nonvolatile gas is introduced into the pressurized container 11 and the raw material is heated and melted, the seed crystal 22 attached to the pulling shaft 21 is immersed in the raw material melt 14 through the capsule material 15.

Thereafter, by starting pulling, a single crystal 23 will be obtained.

In the case of such crystal production, multiple heat insulating cylinders 18 are arranged along the outer periphery of the heating element 17 in order to ensure the heating efficiency and heat insulation effect of the heating element 17 and to maintain an appropriate temperature distribution within the crucible 12. Ru. Carbon products, which are easy to pressurize and are inexpensive, are usually used for the heat insulating cylinder 18, but since carbon has good thermal conductivity, it is necessary to have sufficient heat insulation effect and ensure heating efficiency of the heating element. , it is necessary to take structural measures such as making the insulation cylinders 18 have a multilayer structure or placing a heat insulating material between the heat insulation cylinders having a rough multilayer structure, and as a result, a large amount of carbon products is used.

However, these carbon products are not only eroded and deteriorated by trace amounts of oxygen and water vapor in the atmosphere, resulting in a significantly shortened service life, but also carbon waste from the heat insulating cylinders mixed into the melt of the raw material, causing single crystals to deteriorate. or be incorporated into the growing crystal. Carbon incorporated into the crystal has an adverse effect on crystal properties, such as inhibiting semi-insulating properties of GaAS single crystals, which are important for electronic devices.

Under these circumstances, there is a need for a thermal insulation cylinder that does not become a source of carbon impurities and is thermally and chemically stable.
Furthermore, if the heating efficiency of the heating element can be ensured with a simple configuration, there will be great industrial advantages.

[Purpose of the invention]

An object of the present invention is to provide a compound semiconductor single crystal production device that can pull and produce a compound semiconductor single crystal without causing carbon impurity contamination from a heat insulation cylinder, and that can extend the life of the heat insulation cylinder. There is a particular thing.

[Summary of the invention]

The gist of the present invention is to use a sintered body of aluminum nitride instead of conventional carbon as a heat-insulating cylinder.

That is, the present invention provides an apparatus for producing a compound semiconductor single crystal by the LEC method from a raw material melt in a crucible disposed in a high-pressure container, in which a heating element is provided on the outer periphery of a heating element that heats the raw material melt. The heat insulating cylinder includes a plurality of cylinders made of a sintered body of aluminum nitride that surrounds the heating element twice or more, and a granular filler made of a sintered body of aluminum nitride filled in the gaps between these cylinders. It is made up of:

〔Effect of the invention〕

According to the present invention, since the cylinder and the filler constituting the insulator are formed of a sintered body of aluminum nitride, the following effects (1) to (4) can be obtained.

■ Carbon impurity contamination from pulling furnace parts is reduced,
Improves crystal quality. Furthermore, since the A42N member has excellent durability and heat retention effect, it is possible to maintain an appropriate temperature distribution within the crucible. As a result, the reproducibility of single crystal production has improved.

■ It is easier to assemble and install compared to conventional heat insulation tubes made of carbon products. Conventionally, there is a heat insulation cylinder in which a cloth-like insulation material is placed between two carbon cylinders, but in this case, it is necessary to wrap the insulation material around the inner cylinder and then cover it with the outer cylinder. Its assembly and installation are troublesome.

On the other hand, in the present invention, it is only necessary to fill the gap between the inner and outer cylinders with a filler after installing the inner and outer cylinders, so that the above-mentioned effects can be obtained.

(2) Due to the reasons mentioned above, the design of the furnace section became easier, which also made it easier to expand the furnace section, making it possible to produce crystals with a larger diameter.

(Example of the invention) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a sectional view showing a schematic configuration of a single crystal manufacturing apparatus according to an embodiment of the present invention. Reference numeral 11 in the figure is a high-pressure container made of stainless steel or the like.
A crucible 12 made of AN and having an inner diameter of 100 L slI is disposed via a crucible holder 13. The crucible 12 houses a raw material melt 14 and a liquid capsule material 15 such as 820s.

The crucible 12 is rotated by a rotating shaft 16.

On the other hand, a heating element 17 is arranged on the outer periphery of the crucible 12 so as to surround the crucible 12. This heating element 17 heats and melts the raw material and capsule material contained in the crucible 12 to form the raw material melt 14 and liquid capsule material 15. A heat-retaining tube 20 according to the present invention is disposed on the outer periphery of the heating element 17. In addition, 2 in the figure
1 is a crystal pulling axis, 22 is a seed crystal, and 23 is a pulled single crystal.

As shown in FIG. 2, the heat retaining cylinder 20 includes two cylinders 20a made of AgN sintered bodies with different diameters.

Granular filler 20 made of a sintered body of 20b and AflN
It is composed of c. That is, two cylinders 20a, 2
Qb is arranged coaxially surrounding the heating element 17, and a gap (for example, 10 g) between these cylinders 20a and 2Qb is filled with a filler 20C. Here, as the filler 20G, 3 to 10 [al+] Al2N granular sintered bodies were used.

Next, a crystal manufacturing method using the above apparatus will be explained.

First, 800 [g] of GaAs raw material was placed in the crucible 12,
820x h7 cell material e180 [g], high pressure container 1
It was placed within 1. Next, the inside of the high pressure container 11 is filled with Ar gas 7.
The crucible 12 was heated by the heating element 17 in a pressurized state of [at+i], the GaAs raw material and the encapsulant were melted, and the liquid encapsulant 15 was positioned on the raw material melt 14 .

After dissolving the GaAS raw material, the seeding temperature is adjusted to the optimum condition, and then the seed crystal 22 is brought into contact with the GaAs raw material melt 14 through the liquid encapsulant 15 as shown in FIG. 15, when the pulling speed is 9, [a*/hr], and the pulling rotation is 10.
When crystals were produced under pulling conditions such as [rpl and crucible rotation of 15 [rom], the temperature distribution inside the crucible was sufficiently optimized and stable GaAs single crystal production was possible. .

Furthermore, when GaAs single crystals were repeatedly produced using the above method, not only did the yield of the single crystals become high, but the amount of carbon impurities mixed into the crystals was reduced. Here, when manufactured by the conventional method, carbon contamination of 1X10"[CI&'] was observed, but in this example, a one-digit decrease of 1X10" [α°3] was observed. In general, it was found that the deterioration of the heating element and furnace members was reduced, and the service life was extended, resulting in a significant improvement.

Thus, according to this embodiment, by forming the heat retaining cylinder 20 from a sintered body of AgN, carbon contamination of the single crystal produced by pulling can be significantly reduced. Furthermore, corrosion and deterioration of the heat insulation cylinder 20 are significantly reduced, and the heat insulation cylinder 20 is
0 life can be extended. Also, circles 1120a, 2O
Since the structure is such that the filler 20G is filled in the gap between b, there are also advantages such as ease of assembly and installation.

Note that the present invention is not limited to the embodiments described above. For example, the number of cylinders constituting the heat retaining cylinder is not limited to two, but may be three or more. Furthermore, conditions such as the diameter and height of the cylinders and the gap between the cylinders may be adjusted as appropriate depending on the specifications.

Similarly, the particle size of the filler can also be changed as appropriate depending on specifications. Further, the sintered body forming the cylinder and the filler is not limited to aluminum nitride alone, but may be any body containing aluminum nitride as a main component. Furthermore, it goes without saying that the present invention is not limited to GaAS and can be applied to the production of other compound semiconductor single crystals. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a schematic configuration of a compound semiconductor single crystal manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a partially cutaway perspective view showing the configuration of a heat-retaining cylinder used in the above-mentioned apparatus. Third
The figure is a sectional view showing a schematic configuration of a conventional device. DESCRIPTION OF SYMBOLS 11... High pressure container, 12... Crucible, 13... Crucible holder, 14... Liquid capsule material, 15... Raw material melt, 16... Rotating shaft, 17... Heating element, 20...
・Heat insulation cylinder, 20a, 20b...Cylinder, 20c...Filler, 21...Pulling shaft, 22...Seed crystal, 23
...pulled single crystal. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Tsuba Figure 2

Claims (1)

[Claims] LE from raw material melt in a crucible placed in a high-pressure container
In an apparatus for producing a compound semiconductor single crystal by method C, a sintered body made of aluminum nitride material surrounds the heating element twice or more, and a heat-retaining tube is placed on the outer periphery of the heating element that heats the raw material melt. 1. An apparatus for manufacturing a compound semiconductor single crystal, comprising: a plurality of cylinders; and a granular filler made of a sintered body of aluminum nitride, which is filled in the gaps between the cylinders.