Current status and future prospects of ammonothermal bulk GaN growth

Abstract

This paper reviews the current status of ammonothermal GaN growth at SixPoint Materials, Inc., and discusses challenges in the commercialization of the technology. Small prototype bulk GaN crystals show a high-quality microstructure as well as improved transparency. The full width at half maximum of the X-ray rocking curves from 002 and 201 diffractions typically ranges from a few tens to a few hundred arcsec. The minimum optical absorption coefficient at 450 nm is currently 4 cm-1. To commercialize this technology, expansion of the crystal size is essential. Future tasks include the development of a large reactor, the preparation of large seed crystals and the reduction of the number of cracks in crystals.