JPH0426593A - Compound single crystal manufacturing device and manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a liquid-enclosed pulling method (hereinafter abbreviated as LEC method).
The present invention relates to an apparatus for producing single crystals of compounds such as GaAs+ GaP and InP, and a method for producing single crystals of compounds using this apparatus.

[Conventional technology]

Single crystals of compounds such as GaAs, GaP, and InP are usually produced by the LEC method. In this method, as shown in Fig. 2, raw material 2 is charged into a crucible 1, and B
Z(h3) is placed as a liquid sealant, heated by a heater 4 in a pressurized inert gas atmosphere to melt the raw material 2, and then a seed single crystal 6 attached to the lower end of the rotating pulling shaft 5 is heated. The seed single crystal 6 is brought into contact with the melt and controlled by the heater 4.
A single crystal 7 is grown under the .

However, compound single crystals grown by such an LEC method generally have a high density of dislocations, and since these dislocations have an adverse effect on device characteristics, it is required to reduce the dislocation density as much as possible.

Dislocations are thought to occur and multiply due to thermal stress received at the solid-liquid interface during crystal growth and in the space through which the grown crystal passes, and various measures have been devised to reduce the temperature gradient. One of them is a method using a multi-stage heater as shown in FIG. 3 (for example, Japanese Patent Application Laid-Open No. 60-46998). In this method, two or more sets of heaters (three sets of heaters 4a, 4b, and 4c in Figure 3) are stacked vertically along the outer wall of crucible 1, and the output of each heater is controlled to create a low temperature gradient. This is what we are trying to achieve.

[Problem to be solved by the invention]

However, with the multi-stage heater as described above, although the temperature gradient is improved, the heater to be controlled and the crystal growth space to be controlled are too far apart, and disturbances caused by the convection of the liquid sealant and pressurized gas between them This causes problems such as insufficient responsiveness of temperature environment control (diameter control becomes difficult and growth tends to become unstable).

The object of the present invention is to provide a compound single crystal production device that is capable of achieving low temperature gradients, good responsiveness, and highly accurate temperature environment control;
An object of the present invention is to provide a method for producing a compound single crystal using the same.

[Means to solve the problem]

To achieve the above object, the apparatus of the present invention is characterized in that a first heater is arranged along the outer wall of the crucible, and a second heater that is movable up and down is arranged along the inner wall of the crucible. In addition, in the method of the present invention using this device, after melting the raw material with a first heater arranged along the outer wall of the crucible, a second heater is lowered into the crucible, and crystal growth is started from the beginning of crystal growth. The feature is that the temperature environment of the space is mainly controlled by the second heater.

FIG. 1 is a diagram conceptually showing the apparatus of the present invention, in which a first heater 4 is arranged along the outer wall of the crucible 1, and a second heater 8 is arranged inside the crucible 1. The heater 8 is connected to a lifting device (not shown) so that it can move up and down along the inner wall of the crucible 1, and can be controlled independently of the first heater.

To manufacture a single crystal using such an apparatus, firstly, the raw material 2 and the liquid sealant 8.033 charged in the crucible 1 are
The second heater 8 is then lowered and placed at a predetermined position inside the crucible 1, and the rotating pulling shaft 5 is lowered and attached to the lower end while controlling the temperature of the crystal growth space. After bringing the seed single crystal 6 into contact with the raw material melt 2, the pulling shaft 5 is raised while gradually lowering the temperature by controlling the second heater and the first heater, and the pulling shaft 5 is raised under the seed crystal 6. single crystal 7
It causes growth.

[For production]

In the present invention, the first heater is used to maintain the molten state of the raw material, and the second heater is mainly used to control the temperature environment of the crystal growth space. If the melt temperature is too high when the seed crystal 6 is brought into contact with the melt 2, the seed crystal will be eroded and damaged, so it is necessary to control both the first heater and the second heater to adjust the temperature to the optimum temperature. Since the temperature gradient in the crystal growth space is exclusively controlled by the second heater, the temperature gradient is determined first, the output of the second heater is determined, and then the melt temperature is brought to a predetermined temperature using the first heater. It's good to adjust.

As the single crystal 7 grows, the temperature gradient in the crystal growth space also changes, so in order to keep it almost constant, the output and position of the second heater can be changed.

Further, the second heater may be arranged in multiple stages and each stage may be controlled.

Since the second heater comes into direct contact with the liquid sealant and the raw material melt as described above, it must not be a substance that reacts with or contaminates the liquid sealant and raw material melt. Graphite heaters are relatively free of contamination, but since a trace amount of contamination may affect the semiconductor properties, it is desirable to apply an inert coating, and those coated with BN, AlN, etc. are preferable.

〔Effect of the invention〕

According to the present invention, not only can the temperature gradient be improved, but since the second heater is close to the growing crystal, the responsiveness of the control is greatly improved, the growth is stable, and the diameter can be easily controlled. This has made it possible to efficiently produce compound single crystals with low dislocation density.

[Brief explanation of drawings]

Figure 1 is a diagram conceptually showing the device of the present invention, Figures 2 and 3
The figure is a conceptual diagram of a conventional device. l... Crucible, 2... Raw material, 3... Liquid sealant, 4... Heater, 5... Rotating pulling shaft, 6... Seed single crystal, 7... Single crystal , 8... second heater.

Claims (2)

[Claims] (1) A compound single crystal pulling device that heats and melts the crystal raw material in a crucible using a heater, with a first heater placed along the outer wall of the crucible, and a first heater that can be moved up and down along the inner wall of the crucible. A compound single crystal manufacturing apparatus, comprising: a second heater disposed in a second heater; (2) After melting the raw material with the first heater placed along the outer wall of the crucible, the second heater is lowered into the crucible, and the temperature environment of the crystal growth space from the start of crystal growth is mainly controlled by the second heater. 2. A method for producing a compound single crystal using the production apparatus according to claim 1, wherein the production method is controlled by a heater.