Innovative Techniques for Fast Growth and Fabrication of High Purity GaN Single Crystals

The ammonothermal method involves an upper and lower temperature difference that is provided in an autoclave by a baffle plate, and GaN, which is dissolved in supercritical ammonia in the raw material dissolution region and deposited on a seed crystal in the crystal growth region. Because dissolution and deposition can be continuously performed in an autoclave, this is a suitable method for producing large crystals. The growth of bulk GaN single crystals by the ammonothermal method is currently under development and there remain many indeterminate factors. This chapter describes the technological developments to achieve a high-speed growth and high quality of grown crystals.