JPS59131593A - Apparatus for producing compound semiconductor single crystal - Google Patents

Abstract

PURPOSE:To prevent the damage of a heating furnace in the case of using AC electrical source for the application of magnetic field, by reinforcing the heater of the resistance heater of the titled apparatus with a reinforcing member. CONSTITUTION:The objective apparatus for producing a compound semiconductor single crystal by pulling method is composed of a pressure vessel 1 and a device 6 for applying magnetic field placed at the circumference of the pressure vessel 1, wherein the heater 7 arranged to the side of the resistance heating furnace 3 is reinforced directly with an insulating reinforcing member such as alumina, etc. First, the top of the heater 7 is reinforced with a U-shaped reinforcing member 2a. The lower part of the heater 7 is reinforced by fitting a ring reinforcing member 12b to the outer surface and the bottom of the heater, and fitting another ring reinforcing member 12c to the lower part of the inner surface of the heater 7. Since both edges of the heater 7 are fixed with the reinforcing members 12a-12c, the fatigue of the heater is suppressed even by applying alternate or pulse magnetic field, and the breakage of the heater 7 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compound semiconductor single crystal manufacturing apparatus equipped with a magnetic field application device.

■-■ group compound semiconductors, especially gallium arsenide (Gaps)
) has high electron mobility and is becoming widely used as a crystal substrate for elements of ultrahigh-speed integrated circuits and opto-electronic integrated circuits. The reason why GaAs is attracting attention is that high-quality GcLA8 has a specific resistance of 10'7Ω, 07+ or more, which is a high insulating property, and it has few defects in the crystal, making it possible to obtain a product with a uniform distribution. In addition, it is easy to manufacture large wafers. GaA that meets these requirements
The liquid encapsulation pulling method (LE) is a method for producing s single crystals.
Method C) is attracting attention. This sealing pulling method is known as a low pressure sealing pulling method and a high pressure sealing pulling method. The low-pressure sealing and pulling method uses a gap created using the boat growth method.
Since the raw material is polycrystalline S, the purity of the raw material is low and it is necessary to add chromium and p to make it semi-insulating, which is not preferable. In addition, in the high-pressure sealed pull-up method that performs direct synthesis, chromium is added by the manufacturer, but the crystal raw materials GcL and A8 and the liquid sealant boron oxide (Btos) are heated under high pressure and synthesized. Therefore, the crystal raw material melt melting in the crucible becomes extremely unstable due to thermal convection, and since the crystal growth operation is performed in such a state, the shape of the solid-liquid interface changes drastically. However, minute growth striations occur in the constituent crystals due to thermal fluctuations, and the dislocation distribution of the crystals tends to be non-uniform.

When a device is formed using such a crystal substrate, defects formed in the crystal substrate cannot be controlled, so electrical characteristics,
It has been difficult to manufacture integrated circuits with uniform device characteristics with good reproducibility.

By the way, silicon (Sj) and indium antimony (
It has been reported that in the production of IyzSb) single crystals, a crystal pulling operation is performed while applying a magnetic field. When a magnetic field is applied to the above-mentioned Gaks melt, the generation of thermal convection in the melt is suppressed, and crystal growth occurs in a stable state at the solid-liquid interface, so growth stripes are less likely to occur and high-quality gaps are produced.
It was found that s single crystal could be obtained.

However, resistance heating furnaces for single crystal manufacturing equipment are usually heated by applying alternating current or pulsating current, and as mentioned above, applying a magnetic field tends to damage the heating furnace due to magnetic force, so the supplied current must be converted to direct current. Converting such a large amount of power to direct current is not easy, and since most single crystal pulling equipment is designed to use an alternating current power source, major modifications are required.

An object of the present invention is to provide a compound semiconductor single crystal manufacturing apparatus that uses alternating current as a power source and whose heating furnace is not damaged even when a magnetic field is applied.

Figure 1 shows a single crystal manufacturing apparatus for carrying out the high-pressure liquid sealing pulling method, which is known as the direct synthesis method for Gaks single crystals. A crucible λ of covered quartz, boron nitride, etc. is provided,
(77) The crucible is supported so as to be able to rotate and move up and down on a rotation support shaft μ, and a resistance heating furnace 3 is provided around the crucible λ to heat and maintain the crucible at a predetermined temperature. At the top of Ruppoko is a pulling shaft with a seed crystal attached to the bottom end!
is installed vertically, and the pulling shaft is configured to rotate and move up and down. A magnetic field application device B is installed on the outer periphery of the high-pressure container L, and applies a magnetic field to the crystal raw material melt melted in the melt.

As shown in Fig. 2, the resistance heating furnace 3 has graphite heater members 7 arranged in a comb-teeth pattern on the side surface, and an insulating material is interposed in the gap between each heater member to prevent minute vibrations. This improves safety.

A hole is provided in the center of the bottom surface of the heating furnace 3 through which a rotary support shaft supporting the crucible passes through, and a heater electrode // is provided protruding downward from the bottom surface, and the heater member is connected by a screw /θ. (Fig. 5).

When a magnetic field is applied from the lateral direction (arrow %B#) to a heating furnace with such a structure as shown in Figure 3, a force is applied that pulls the heater member in a direction 90 degrees off from the direction of the magnetic force. (arrow mark Fl) In particular, when the heating furnace is operated under alternating current or pulsed conditions, the direction of the force applied to the heater member constantly changes, which causes fatigue to occur quickly and the heater member to be easily damaged. Therefore, until now, when applying a magnetic field, the heating furnace had to be improved and the heating furnace made by ``(Yen + 1.L%)'' was used.

However, in the present invention, the heater member is directly reinforced using an insulating reinforcing member. First, the upper edge of the heater member 7 is reinforced by covering it with a reinforcing member /2α having a U-shaped cross section. An L-shaped annular reinforcing member/cob is fitted to the outer periphery of the lower part of the heater member so as to extend from the outer surface to the floor part υ) for reinforcement. Furthermore, an annular reinforcing member/2c is fitted to the lower part of the inner surface of the heater flat material to reinforce it.If the heater member is reinforced with such a reinforcing member, each tip of the heater member will remain stable even when a magnetic field is applied. Since they are fixed so as not to move by their respective reinforcing members, fatigue is less likely to occur even when operating with alternating current or pulsating current, and damage to the heater members is prevented.

As a material constituting such a reinforcing member, an insulating heat-resistant member such as alumina or pyrolytic boron nitride can be used. The shape and dimensions of the reinforcing member should be determined appropriately within a range that does not affect the thermal efficiency of the heating furnace. In particular, the tip of the heater member is more susceptible to damage due to vibrations, etc., so do not move that part. It is necessary to have such a configuration.

When the heater member of the heating furnace was reinforced as described above, crystal growth was performed by applying a magnetic field of 5000 Gauss to the resistance heating furnace operated by AC power, but no vibration was observed in the heater member, and the result was stable. A single crystal was formed.

Examples of single crystals that can be effectively produced by the apparatus of the present invention include SZ + Gaks' + IiP + 171. Sb
r Garb and the like.

As is clear from the above description, this invention is such that the heater member of the heating furnace is reinforced with a reinforcing member, and therefore it can be applied as is to the already used AC-current single crystal pulling apparatus. By applying a magnetic field and growing crystals from the crystal, the generation of growth stripes can be suppressed and a high-quality single crystal can be formed. It goes without saying that the present invention is effective when applied not only to a crystal pulling apparatus using an AC power source but also to a crystal pulling apparatus using a DC power source.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a single crystal manufacturing apparatus equipped with a magnetic field application device, FIG. 2 is a partially sectional side view showing a heating furnace of the single crystal manufacturing apparatus according to the present invention, and FIG. A cross section of the heating furnace cut along the line ■-■ in Fig. 2. In the figure, / is a high-pressure container, C is a crucible, 3 is a heating furnace, t is a magnetic application device, 7 is a heater member, r is an insulating material, /, 2α,
/1b, /, 2Q indicate reinforcing materials. Patent Applicant: Institute of Industrial Science and Technology, Makoto Nagaishiita, Procedure Amendment Form C) June 1980/J, Commissioner of the Japan Patent Office, Kazuo Wakasugi/, Indication of Case: 1982 Patent Application No. 5182 1, Invention Name of Compound Semiconductor Single Crystal Manufacturing Apparatus 3, Person making the amendment April 26, 1981 (Delivery date) Amendment Target of amendment Drawing B Contents of amendment Figure 3 F Procedural amendment (voluntary) June 1988 7.3rd Japan Patent Office Commissioner Kazuo Wakasugi/Display of the case Patent Application No. 5182 of 1982! 1. Name of the invention Compound semiconductor single crystal production device 3. Amendment to the amendment Contents of the amendment Attached document

Claims (3)

[Claims] (1) In a single-crystal manufacturing apparatus that heats a silt crucible in a resistance heating furnace and grows a crystal by pulling a seed crystal while applying a magnetic field to the crystal raw material melt in the crucible, the heater member of the resistance heating furnace is used. A compound semiconductor single crystal manufacturing device characterized in that the compound semiconductor single crystal is reinforced with a reinforcing member. (2) The single crystal manufacturing apparatus according to claim 1, wherein the reinforcing member is made of alumina. (3) The single crystal manufacturing apparatus according to claim 1, wherein the reinforcing member is made of pyrolytic boron nitride.