Growth of Bulk GaN Crystals by the Basic Ammonothermal Method

Abstract

A remarkable progress was made in GaN wafer fabrication via the basic ammonothermal method. Bulk GaN crystals were grown on GaN platelets in supercritical ammonia at 575 °C and 220 MPa with sodium amide. The grown crystals showed three-dimensional polyhedron shape in size of more than 5 mm. Clear crystallographic facets of N-face and m planes were observed although Ga-face was decorated with angled facets of {1011} planes. X-ray diffraction revealed multiple grains whose individual full width half maximum of ω scan was 200–400 arcsec. C plane and m plane wafers were fabricated by slicing the GaN boules.