Low-cost aluminum nitride crystal growing method

Abstract

The invention discloses a low-cost aluminum nitride crystal growing method. According to the method, a tantalum carbide crucible is substituted with a graphite crucible, wherein a graphite crucible islined with a layer of a tantalum carbide metal shell layer to isolate the graphite crucible so as to prevent from corrosion by aluminum vapor; an aluminum nitride ceramic baffle with holes is arranged in the crucible to sandwich an aluminum nitride powder source with characteristics of large specific surface area and small particle size between the graphite crucible and an internal material source, such that gas is subjected to preliminary filtering, a chemical reaction with the graphite impurity is performed, oxygen atoms are removed, and carbon impurities are separated; the medium-size aluminum nitride powder particles in the middle-lower interlayer provide a secondary filtration effect; and a large-particle and highly-purified aluminum nitride source grows at the top of the material source, such that the large-size centimeter-scale aluminum nitride single crystal with characteristics of less impurities and high crystal quality (no crack and no micropore) is obtained.

Description

technical field [0001] The invention relates to the field of preparing large-diameter aluminum nitride bulk single crystals by a sublimation method, in particular to a low-cost aluminum nitride crystal growth method. Background technique [0002] AlN crystal is an important wide bandgap (6.2eV) semiconductor material with high thermal conductivity (3.2W.cm -1 K -1 ), high resistivity and high surface acoustic velocity (5600-6000m / s) and other excellent physical properties, it is widely used in lasers, high-power electronic devices, optoelectronic devices and surface acoustic wave devices. At present, physical vapor transport (PVT) is recognized as an effective way to prepare large-sized aluminum nitride single crystals, and AlN crystals are grown on substrates by sublimation. [0003] Currently, tantalum carbide crucibles are commonly used. However, the crucibles are expensive, have a short lifespan, are high-consumption products, and require a long carbonization process b...

AI Technical Summary

Problems solved by technology

[0003] Currently, tantalum carbide crucibles are commonly used. However, the crucibles are expensive, have a short service life, are high-consumption products, and require a long carbonization process before being used for single crystal growth.

The crucible has high requirements on the growth process, and the low content of oxygen permeation at high temperature (600°C) may cause damage to the crucible

According to test statistics, the crucible has short service life, serious cracking and high cost

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