High-pressure process to produce GaN crystals

High melt temperature and thermal decomposition prevent the use of standard bulk semiconductor crystal growth processes for the production of GaN. We have employed a hydrostatic pressure system to grow GaN crystals. An ultrah igh pressure, high temperature process was developed using a solid-phase ni trogen source to form GaN crystals in a Ga metal melt. Using a thermal grad ient diffusion process, in which nitrogen dissolves in the high temperature region of the metal melt and diffuses to the lower temperature, lower solu bility region, high quality crystals up to similar to1 mm in size were form ed, as determined by scanning electron microscopy, x-ray diffraction, and m icro-Raman analysis. (C) 2000 American Institute of Physics. [S0003- 6951(0 0)00650-1].