Effect of Sb as a surfactant during the lateral epitaxial overgrowth of GaN by metalorganic vapor phase epitaxy

Antimony (Sb), an isoelectronic impurity, has been studied as a surfactant during the lateral epitaxial overgrowth (LEO) of gallium nitride (GaN) by metalorganic vapor phase epitaxy (MOVPE). The presence of Sb in the gas phase was found to alter both the LEO growth rates and the predominant facet formations. Vertical facets to the LEO growth appear with the addition of Sb under conditions that normally produce triangular or sloped sidewalls over a range of growth temperatures. While Sb alters the growth facets, only a small amount of Sb was incorporated into the GaN, suggesting that Sb acts as a surfactant during the GaN MOVPE growth. Sb addition produces surface conditions characteristic of a Ga-rich surface stoichiometry indicating both a possible change in the reactivity of NH3 and/or enhanced surface diffusion of Ga adatom species.