Preparation method of large-size sapphire crystal dynamic temperature field

Abstract

The invention relates to a preparation method of a large-size sapphire crystal dynamic temperature field. The preparation method is characterized in that a heating body of a crystal growth furnace consists of an auxiliary heating body and main heating bodies, wherein the main heating bodies include main heating bodies at the lower part of the bottom of a crucible and a main heating body outside the wall; the heating bodies are made of tungsten filaments; and the three heating bodies are independently controlled by corresponding temperature control systems respectively. Through independent power regulation of the three heating bodies, the problems such as tiny bubbles in large-size sapphire crystal and difficult crystal growth caused by different requirements of shouldering and equal-diameter growth on the temperature field are solved by use of a dynamic temperature field in the processes of raw material melting, shouldering and equal-diameter growth of crystal growth. The adopted dynamic temperature field has the characteristics that high axial gradient is adopted in raw material melting, a large radial temperature gradient is adopted on the melt surface in the crystal shouldering stage, and a small radial temperature gradient is adopted at the solid-liquid interface in the equal-diameter growth process of crystal.

Description

technical field [0001] The invention relates to a method for preparing a large-size sapphire crystal, in particular to a method for preparing a dynamic temperature field of a large-size sapphire crystal. Background technique [0002] Large-sized sapphire crystal has excellent optical and mechanical properties, good physical and chemical stability, high strength, high hardness, and can work at a high temperature of 1800 ° C. It is a lining for LEDs, large-scale integrated circuits SOI and SOS, and superconducting nanostructure films. Bottom material, and can be used as window material for infrared military devices, space satellites and high-intensity lasers. As application requirements evolve, new demands are placed on crystal size and quality. However, new difficulties arise when growing larger-sized sapphire crystals, mainly manifested in that the shouldering process of the crystal becomes difficult to control, resulting in poor quality of the upper part of the crystal, an...

AI Technical Summary

Problems solved by technology

During the crystal growth process, the convective pattern of the melt is very important to the crystal growth. Mechanical agitation will have a serious impact on the convective pattern of the melt, making the solid-liquid interface unstable, and producing a large number of defects in the melt, resulting in a change in the quality of crystal growth. Bad, moreover, in the melt above 2050°C, the stirring rod will generate impurities in the melt, and these impurities will quickly diffuse in the melt through stirring, and some of them will enter the crystal, resulting in impurity defects in the crystal

Therefore, although this method realizes that the bubbles in the melt need to be driven out, the method used will seriously reduce the quality of crystal growth, and it is difficult to use in actual crystal growth.

[0005] Therefore, although the above-mentioned invention patent hopes to solve the problem of misalignment between the cooling center and the geometric center of the crucible during the shoulder-setting process during the growth of large-sized sapphire crystals (patent No. 200510010116.4) and the problem of bubbles in the melt (patent No. 200410008593.2), the method adopted There are limitations, it is difficult to apply in large quantities in actual mass industrial production

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