Synthesis of AlN single crystal by solution growth method using type 430 ferritic stainless steel flux

We propose a new AlN crystal growth method using Fe-based fluxes. AlN single crystals with a thickness of 67-212 mu m were epitaxially grown on an AlN bulk substrate by a solution growth method using type 430 ferritic stainless steel flux. The full width at half maximum values of the x-ray rocking curves of (0002) and (10-12) of the synthesized AlN were 137 and 83 arcsec, respectively. The impurity concentrations of carbon were significantly decreased from 3 x 10(19) atoms/cm(3) in seed crystal to 6 x 10(17) atoms/cm(3) in synthesized crystal. The features of the method developed in this study are described as follows: (1) steel-based alloys are used as a flux, which are readily available and low-cost; (2) the growth temperature is 1700 degrees C, which is much lower than that of the sublimation method; (3) no high-pressure vessel is required because growth can be performed under 1 atmospheric pressure conditions; and (4) waste gas detoxification equipment is not required because only N-2 gas is used and no toxic or flammable gases are used. Because of the above features (1) through (4), this is an effective crystal growth process from the perspective of ensuring the economics and safety of the facility. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).