Modeling Study of Hydride Vapor Phase Epitaxy of GaN

The mechanisms of GaN growth by Hydride Vapor Phase Epitaxy (HVPE) in a horizontal reactor are studied both theoretically and experimentally. A strong effect of gas dynamics and species transport on the growth rate and V/III ratio over the substrate is revealed. It is shown that the experimentally observed non-uniformity of the growth rate is related to pushing off the gaseous GaCl by ammonia stream supplied into the reactor. A surface kinetic model is suggested based on the assumption that blocking of the GaCl adsorption sites by Cl and H adatoms on the GaN surface is the mechanism of kinetic limitation of the growth rate. The theoretical results obtained agree well with the experimental observations.