A low-cost method for growing aluminum nitride crystals

Abstract

The invention discloses a low-cost aluminum nitride crystal growth method. In the method, a graphite crucible is used to replace a tantalum carbide crucible, and a layer of tantalum carbide metal shell is lined inside the graphite crucible to insulate the graphite crucible to prevent corrosion by aluminum vapor. The aluminum nitride ceramic baffle with holes is used inside the crucible to sandwich the aluminum nitride powder source with a large specific surface area and a small particle size between the graphite crucible and the internal source to initially filter the gas and remove graphite impurities. Chemical reaction occurs, oxygen atoms are removed, and carbon impurities are isolated; the medium-sized aluminum nitride powder in the middle and lower interlayer plays the role of secondary filtration, and the top of the material source is made of large-particle highly purified aluminum nitride material. Growth, and finally obtain a large-size centimeter-scale aluminum nitride single crystal of aluminum nitride with less impurities and higher crystal quality (no cracks, no micropores).

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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