Manufacturing method of large-size C-oriented sapphire crystals

Abstract

The invention relates to a manufacturing method of large-size C-oriented sapphire crystals. According to the method, an alumina raw material with the high purity of 99.999 wt% is adopted and is heated to be molten and subjected to crystal seeding and crystal growing. A main heater and an assistant heater are adopted, wherein a tungsten rod cylinder-shaped heating body is arranged around a crucible and is used as the main heater; another tungsten disc-shaped heating body is arranged at the bottom of the crucible and is be used as the assistant heater; the power ratio of the main heater to the assistant heater is (20 to 80 KW): (10 to 60 KW). In addition, a tungsten tube is mounted at the top of the crucible, and argon is introduced into the tungsten tube to regulate the temperature of the seed crystal and a liquid surface. As the method is used, the temperature distribution of a longitudinal temperature field in the crucible is improved, so that air bubbles, cracks and other defects are avoided or reduced, i.e., the seed crystal is prevented from being molten at overhigh temperature during the crystal seeding process. Therefore, the generation of a C-oriented long crystal boundary with a small angle is controlled effectively. As a result, the growing C-oriented crystals with the diameter of 14 inches are good in position staggering density and single crystal performance. Consequently, the method provided by the invention reaches the international advanced level.

Description

technical field [0001] The invention belongs to a method for manufacturing a sapphire single crystal, in particular to a method for growing a large-size (maximum crystal diameter of 14 inches) C-oriented sapphire single crystal. Background technique [0002] Sapphire has a high melting point (2045°C), high hardness (9 on the Mohs scale, second only to diamond), and good light transmittance (high light transmittance in the ultraviolet, visible, and infrared bands, and transmittance at 3-5 μm Pass rate as high as 85%), strong radiation resistance, high tensile strength, corrosion resistance, high thermal conductivity, good thermal shock resistance and other good properties, becoming the most widely used oxide substrate material, mainly used as a semiconductor Film substrate materials, LED chip substrate materials, large-scale integrated circuit substrates, etc. In addition, sapphire crystal is also an excellent window material for infrared military devices, missiles, submarin...

AI Technical Summary

Problems solved by technology

[0008] However, the degree of lattice deformation when growing C-oriented sapphire single crystals is significantly greater than that of other directions. Due to the anisotropy of sapphire single crystals, any heterogeneous nucleation will easily lead to cracking of sapphire single crystals.

Therefore, it is difficult to directly grow large-size, high-quality C-oriented sapphire crystals

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