AlN bulk single crystal growth on SiC and AlN substrates by sublimation method

Abstract

Aluminum nitride (AlN) bulk single crystals up to 45 mm in diameter and 10 mm in thickness have been successfully grown on 6H-SiC(0001) substrates by the sublimation method. Moreover, high growth rate of 200μm/h has been achieved by high temperature homo-epitaxial AlN growth on AlN(0001) substrate. The Raman spectrum indicates that the polytype of the grown AlN single crystals is a Wurtzite-2H type structure, and the crystals do not include any impurity phases. In both the hetero- and homo-epitaxial AlN bulk single crystal growth, the quality at the top of the crystal improves as the crystal thickness increases along the <0001> direction during the growth: low etch pit density 7 × 104 cm−2 and 1 × 104 cm−2 have been achieved at a thickness of 8 mm and 2 mm in the hetero- and homo-epitaxial growth, respectively.