Hydride Vapor Phase Epitaxy (HVPE) is a process that can produce single crystal GaN. It is used for the growth of GaN substrates because of the high growth rate and high quality that can be attained. In this process, HCl gas is reacted with liquid gallium metal, which forms GaCl gas. Then the GaCl reacts with NH₃ gas at about 1,000 °C to form the solid crystal of GaN. Eta Research has developed our own HVPE equipment with the goal to cost effectively scale the production of GaN wafers.
Presently, the vast majority of GaN-based devices use foreign substrates such as Al₂O₃ and Si. Although foreign substrates are good for some applications, the dissimilar material causes defects to be placed in the GaN device layers as material is deposited. The defects can reduce the performance.
GaN substrates, especially with low defect density, offer the best choice for deposition of GaN device layers. Use of GaN substrates will improve the efficiency, power density, and other performance metrics of GaN devices.