Properties of Ammonothermal Crystals

This chapter summarizes the present status of bulk GaN crystals grown by ammonothermal basic and acidic methods, and reviews their intrinsic physical properties. Crystals with low dislocation densities, typically well below 105 cm−2, high crystal lattice flatness, and sharp X-ray rocking curves (typically below 20 arcsec) are reproducibly grown by both methods. High quality strain-free homoepitaxial films have been successfully deposited on both polar and non-polar ammonothermal substrates. Characteristics of testing devices produced using these epitaxial templates confirm the potential of ammonothermal substrates for fabrication of high performance and high yield devices.