2.03 - Growth of bulk GaN crystals for the production of substrates

This chapter provides detailed information on gallium nitride crystal growth technology as well as the preparation of substrates and their structural properties. Three methods of growing gallium nitride crystals are presented, focusing on two of them: alkaline ammonothermal crystallization and from the gas phase, the so-called halide vapor phase epitaxy. The morphologies of the growing crystals are characterized in detail. The technological path to be followed from the crystal to obtaining substrates from it is shown. The structural properties of ammonothermal gallium nitride substrates are described in great detail, describing the results of high-resolution X-ray diffractometry and X-ray topography. Electrical and optical properties of substrates are mentioned. Prospects for crystallizing gallium nitride to produce larger substrates for electronics and optoelectronics applications are outlined.