JP3560067B2 - Single crystal growth method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for growing a single crystal used for electronic equipment and the like.
[0002]
[Prior art]
In the method of heating the crucible to melt the raw materials in the crucible, bringing the seed crystal into contact with the melt, and gradually raising the seed crystal to grow a single crystal having cleavage, so that cleavage cracks do not occur I was growing up.
[0003]
[Problems to be solved by the invention]
However, this method requires a step of using an X-ray diffractometer or the like to know the cleavage direction and the crystal orientation before taking a sample. The present invention provides a method of omitting or simplifying this orientation step.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors heated a raw material in a crucible into a melt, contacted the lower end of the seed crystal with the melt, and grown a single crystal while pulling up the seed crystal. In the growth of the crystal, by making the shape of the solid-liquid interface during the growth of the straight body part convex on the melt side by 10% to 30% of the crystal diameter, a minute cleavage crack is generated in a part of the crystal, The present invention has been made because it has been found that, by knowing the direction of the cleavage plane, the process for knowing the crystal orientation can be omitted or simplified. Some of the crystals, Te single crystal - a pole tip.
[0005]
[Action]
The raw material in the crucible is heated to form a melt, the lower end of the seed crystal is brought into contact with the melt, and the seed crystal is pulled up to grow a single crystal having cleavage. If it has, at least in the tail portion of the single crystal, the single crystal is grown under the condition of projecting 10% to 30% of the crystal diameter to the melt side of the solid-liquid interface, so that only a part of the crystal is grown. The causes that can cause minute cleavage cracks are considered as follows. If the shape of the solid-liquid interface is raised to the melt side by 10% to 30% of the crystal diameter, an extremely large tensile stress is locally generated at the tip of the tail of the crystal when the crystal is cut off from the melt . The large range of the tensile stress is a small range at the tip of the tail, and a compressive stress is generated around the small range. This was confirmed by computer simulation. Therefore, the crystal cracks only at the tip of the tail, and the cracks remain only at the minute portions.
[0006]
【Example】
Comparative Example An example in the case of a cerium-activated gadolinium silicate single crystal (Ce: Gd ₂ SiO ₅ ) will be described. As raw materials, about 3240 g of Gd ₂ O ₃ , about 560 g of SiO ₂ , and about 10 g of CeO ₂ were placed in a φ100 Ir crucible, and crystals of φ50 × 180 mm were grown by the Czochralski method.
The crucible was heated by high-frequency induction heating to obtain a melt as a raw material, and a crystal was grown while being pulled at 1 to 5 mm / hour. When growing the straight body, the rotation speed of the crystal was set to 40 rpm. By this method, a crystal with a flat crystal tail was grown. Each of the obtained crystals had no cleavage crack.
[0007]
Example A GSO single crystal was grown by the Czochralski method as in the comparative example.
An example of a cerium-activated gadolinium silicate single crystal (Ce: Gd ₂ SiO ₅ ) will be described. As raw materials, about 3240 g of Gd ₂ O ₃ , about 560 g of SiO ₂ , and about 10 g of CeO ₂ were placed in a φ100 Ir crucible, and crystals of φ50 × 180 mm were grown by the Czochralski method.
The crucible was heated by high-frequency induction heating to obtain a melt as a raw material, and a crystal was grown while being pulled at 1 to 5 mm / hour. When growing the straight body, the rotation speed of the crystal was 30 rpm. By this method, a crystal having a crystal tail of 10 mm was grown. In the obtained crystal, a cleavage crack having a depth of about 5 mm occurred in the convex portion of the tail of the crystal.
As a result, in the comparative example, a step using an X-ray diffractometer was required to know the direction of the cleavage plane of the crystal, whereas in the example, the direction of the cleavage plane was found without using the X-ray diffractometer. .
In the embodiments of the present invention, the case where the crystal tail is convex 10 mm is described. However, when the tail is convex to the melt side by about 10% to 30% of the crystal diameter, cracks are similarly obtained. When growing a single crystal while contacting the lower end of the seed crystal with the melt and pulling up the seed crystal, growing the crystal diameter from the seed crystal to the target diameter Refers to the stage of nurturing.
[0008]
【The invention's effect】
According to the growing method of the present invention, a process for knowing the direction of the cleavage plane can be simplified for a crystal having cleavage.

Claims (2)

A melt by heating the raw material in the crucible, the melt is brought into contact with the lower end of the seed crystal, the method for growing a single crystal for growing a single crystal while pulling the seed crystal, minute cleavage cracking tail portion of the crystal Wherein the direction of the cleavage plane is known. 2. The method of growing a single crystal according to claim 1, wherein the shape of the tail portion is convex toward the melt from 10 to 30% of the crystal diameter of the straight body portion.