Dynamic-temperature-field preparation method for large-size C-axis sapphire crystal

Abstract

The invention relates to a dynamic-temperature-field preparation method for large-size C-axis sapphire crystal. An employed crystal growth furnace heating body comprises an auxiliary heating body at the upper part of the outer side of a crucible, an auxiliary heating body at the outer side and a main heating body at the lower part of the bottom. A tungsten filament of the auxiliary heating body at the upper part of the outer side of the crucible employs a left part and a right part which are in connection in a parallel way. The power of the auxiliary heating bodies and the main heating body are respectively independently controlled by corresponding temperature control systems. By independently controlling the power of the three heating bodies and utilizing the dynamic temperature field method during crystal growth, temperature fields adaptive to demands of expelling bubbles, expanding shoulder and constant-diameter growth of a crystal are formed in the hearth when the crystal grows. In the constant-diameter growth stage, a horizontal growth interface is employed, the crucible wall temperature is close to the melt temperature, and thus no defect is generated caused by impact of a melt convecting to the middle on the crystal growth solid-liquid interface because of high crucible wall temperature. Heat radiation of the crystal is uniform, and thus the center axis does not have too many defects caused by concentrated heat radiation at the center axis. Therefore, the crystal has less defects, and high-quality C-axis sapphire crystal can be grown and obtained.

Description

technical field [0001] The invention relates to a method for preparing a large-size C-axis sapphire crystal, in particular to a method for preparing a dynamic temperature field of a large-size C-axis 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. The C-side sapphire wafer is usually used as the substrate material for LED coating. The sapphire crystal grown along the C-axis can be directly cut into a C-face sapphire wafer, and the utilization rate of the crystal is high. The development of C-grown sapphire crystal growth technology is important to i...

AI Technical Summary

Problems solved by technology

[0003] The growth quality of sapphire crystals that can meet the [0001] direction used for LED substrates needs to solve three problems: first, the problem of crystal dislocation density must be solved, and high-quality seed crystals must be used to ensure that the seed crystals will not introduce dislocation lines. In the process of crystal growth, it is required that no new dislocation lines appear or as little as possible; secondly, the size of the crystal growth should be as large as possible, close to the growth crucible to obtain better growth efficiency; in addition, it is not possible to introduce dislocation lines between New defects such as growth streaks, etc.

Images