Effect of hydrogen on anisotropy of the p-GaN growth rate in the case of side-wall MOCVD

Abstract

The effect of the composition of the carrier gas on anisotropy of p-GaN growth rates in side-wall metal-organic chemical vapor deposition was studied. p-GaN layers with a nominal thickness of ∼400 nm were grown on side-walls of GaAs mesa stripes formed preliminarily by selective-area epitaxy on Si3N4. It is shown that, if hydrogen is used as the carrier gas, the p-GaN growth occurs mainly in the lateral direction, so that the p-GaN layer is either absent or is thin at the top faces of mesa stripes; in contrast, if nitrogen is used as the carrier gas, growth in the normal (0001) direction is prevalent, so that a p-GaN layer is formed at all faces of the mesa stripe. The results of our study are indicative of a significant role of hydrogen in the process of epitaxial growth of GaN and can be used in the development of technology of devices with p-n junctions based on GaN and with the use of selective-area growth.