JPH0776145B2 - Compound semiconductor single crystal growth equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a compound semiconductor single crystal growth apparatus by a liquid sealing pulling method (LEC method).

[Conventional technology]

III-V group compound semiconductors such as GaAs have a higher electron mobility than Si, and development of ICs and light-emitting devices utilizing their properties is recommended. As a method for growing a single crystal of a III-V group compound semiconductor, a liquid encapsulation pulling method (Liguid Encapsulated Czochr), which is one of the methods for pulling a single crystal industrially, is used.
Alski (LE) method is often used. Since III-V group compound semiconductors have a high dissociation pressure of group V elements near the melting point, the LEC method covers the raw material melt with a liquid sealant such as B ₂ O ₃ and further Ar, N ₂ gas, etc. Is a method for growing a single crystal in an atmosphere pressurized at 5-80 kg / cm ² .

In the LEC method, when pulling a single crystal, a single crystal piece called a seed crystal is used to pull the single crystal from the raw material melt. That is, as shown in FIG. 3, a seed holder (2) equipped with a seed crystal (1) is attached to an inner rod (4) passing through the outer tube (3), and is connected to a lower shaft (10) to apply pressure. The crucible (9) contained in the container (5) is soaked with the seed crystal (1) through the liquid sealant (7) in the raw material melt (8) melted by the heater (6), After being soaked, the single crystal having the same crystal orientation as the seed crystal (1) was pulled from the melt (8). The act of immersing the seed crystal (1) in the raw material melt (8) and blending it is said to be seeding.
The allowable temperature range for seeding and pulling the single crystal is within 10 ° C. In addition, (11) shows the observation window provided in the pressure vessel (5).

[Problems to be solved by the invention]

Conventionally, the steps of seeding and pulling up are performed while observing the condition of the melt surface by visual observation through an observation window. in this case,
Since the temperature of the melt cannot be directly measured, it is necessary to repeat the seeding work to judge the suitability of the temperature of the melt, which causes a problem that work efficiency is low and it is not constant. The present invention has been made in view of the above points, and an object thereof is to provide a compound semiconductor single crystal growing apparatus that reduces the number of trials of seeding, improves seeding work efficiency, and makes it constant. Especially.

[Means for solving problems]

According to the present invention to achieve the above object, a liquid sealing method having a pull-up shaft composed of a seed holder for holding a seed crystal and an inner rod for attaching and rotating the seed holder up and down. In the compound semiconductor single crystal growing device for pulling a single crystal according to the above, there is provided a compound semiconductor single crystal growing device in which a temperature sensing element is embedded and mounted near the lower end of the pulling shaft.

[Action]

There is an optimum raw material melt temperature for seeding, and the allowable temperature range is severely within ± 5 ° C. Therefore, if the temperature of the raw material melt can be accurately known in a short time, the seeding work efficiency is improved. However, since it is difficult to directly measure the high melt temperature, in the present invention, the temperature of the specific portion of the pulling shaft in the seeding state is measured, and the temperature and the melt of the specific portion that have been measured in advance. The method of knowing the melt temperature from the correlation with the temperature is used. The temperature measurement point of the pull-up shaft is appropriate inside the seed holder and inside the crucible side lower end of the inner rod.If the temperature of the seed crystal is directly measured, it is close to the melt surface of the raw material, so the melt temperature is You can know it accurately. Therefore, it is advisable to embed a temperature measuring element such as a thermocouple inside the temperature measuring location. In addition, since the LEC method grows a single crystal under an inert gas pressure, the measurement accuracy can be improved by embedding the temperature measuring element so as not to be affected by gas convection.

〔Example〕

 The present invention will be described below based on the embodiments shown in the drawings.

FIG. 1 is a partial cross-sectional view of a pulling shaft showing an embodiment of the present invention. Make a hole in the tip end of the inner rod (4) on the seed holder (2) side, diagonally downward from the side surface toward the center,
A thermocouple (12) is embedded in this hole.

FIG. 2 is a partial sectional view of a pulling shaft showing another embodiment of the present invention. In this example, the hole formed from the side surface of the inner rod (4) toward the center portion penetrates the center of the seed holder (2) to reach the middle of the seed crystal (1), and the thermoelectric material embedded in the hole is formed. The temperature-sensitive part of the pair (12) is located at the tip of the hole, in the seed crystal (1). In this example, since the temperature of the portion close to the raw material melt is measured, it is possible to know the exact melt temperature, but a hole is formed in the seed crystal for pulling the single crystal, and a thermocouple is set, and pulling is performed. After completion, the complicated operation of removing the set thermocouple occurs.

〔The invention's effect〕

As described above, according to the present invention, since the temperature sensing element is embedded in the vicinity of the lower end of the pulling shaft and mounted, the temperature of the raw material melt can be controlled, the seeding work efficiency is improved, and the temperature is stable. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a pulling shaft according to the present invention, FIG. 2 is a partial sectional view of another pulling shaft according to the present invention, and FIG. 3 is an explanation of a conventional compound semiconductor single crystal growing apparatus by the LEC method. It is a figure. 1 ... Seed crystal, 2 ... Seed holder, 3 ... Outer tube, 4 ... Inner rod, 5 ... Pressure vessel, 6
...... Heater, 7 …… B ₂ O ₃ , 8 …… Material melt, 9 …… crucible, 10 …… bottom axis, 11 …… observation window, 12 …… thermocouple.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-59-227797 (JP, A) JP-B-52-9437 (JP, B2)

Claims (2)

[Claims] 1. A compound semiconductor for pulling a single crystal by a liquid sealing method, which has a pull-up shaft composed of a seed holder for holding a seed crystal and an inner rod for mounting and rotating the seed holder. In the single crystal growing device, a temperature measuring element is embedded and mounted near the lower end of the pulling shaft, and the compound semiconductor single crystal growing device is characterized. 2. The compound semiconductor single crystal growing apparatus according to claim 1, wherein the temperature measuring element is mounted by being embedded in a seed crystal attached to a seed holder.