Method for developing aluminum nitride crystal in large size through flow of plasma flame

Abstract

This invention discloses a method for growing AlN single crystal by heating raw materials with plasma flow. The method comprises: utilizing plasma flow as the heating source, and AlN micropowder or high-purity Al micropowder and N2 as the raw materials, sending the raw materials into plasma flow by using carrier gas, utilizing AlN single crystal as the crystal seed or AlN polycrystal as the matrix material for self-nucleating growth, heating the crystal seed or matrix material by plasma flow or other methods to the temperature need for crystallization, and growing in the growth chamber with N2 as the growth environmental gas. The powder delivery rate is adjustable. The stage for supporting the crystal seed or matrix material can be elevated and rotated with controllable speed. The pressure of N2 is adjustable. This invention also shows the figure for depicting the reaction apparatus for growing AlN single crystal by heating raw materials with plasma flow.

Description

technical field [0001] The invention relates to the preparation of high-temperature semiconductor single crystal materials used in the electronics and optoelectronic industries, especially the preparation method of growing aluminum nitride crystal materials. Aluminum nitride crystal materials are used in all solid-state white light lighting, sterilization and disinfection devices, compact analytical equipment used in biotechnology and pharmaceuticals, biological agent detection systems, compact ultraviolet light sources in covert communications, and short-wavelength lasers used in high-density data storage And many other fields have broad application prospects, in addition, it is also very promising as a substrate material for making nitride semiconductor devices, high-power radio frequency devices, millimeter wave devices and microwave devices. Background technique [0002] International research on aluminum nitride single crystal growth technology can be traced back to the...

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Problems solved by technology

Not to mention that this kind of laboratory-level research results cannot yet achieve industrial production, nor can it meet the quantitative needs of aluminum nitride crystals in various application fields.

The fundamental reason for the above difficulties is that the sublimation crystallization method of aluminum nitride crystals has certain limitations in principle. The specific performance is as follows: ①The sublimation crystallization method uses a material closed or semi-closed system, which is difficult to realize during the growth process. The crystals cannot continue to grow due to the continuous transportation of materials; ② After the raw materials in the system experience several temperature fluctuation cycles, the raw materials will lose their activity, resulting in powder agglomeration, and the sublimation rate of the whole system becomes smaller; ③ Crystal growth rate Difficult to control, especially early in crystal growth

In principle, the crystal growth rate can be controlled by adjusting the temperature and temperature gradient of the sublimation zone and crystallization zone of the growth chamber, but in practice, it is difficult to accurately measure and control the temperature in the high temperature zone; ④ sublimation method Aluminum nitride crystal growth requires a crucible, but the aluminum vapor generated by decomposition at high temperature will severely damage the crucible

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