An atomic-level insight into the surface step edge of GaN

摘要

Power semiconductor devices are playing a leading role in modern power electronic devices. Despite beingSi still the primary material in electronic industry, a general consensus has been reached on the fact theSi-based technology is now reaching its intrinsic limits. Given this scenario, GaN seems to be the bestcandidate for the next leap forward. The major figures of merit of the wide band-gap GaN is a lowerelectric power consumption, with consequent decrease of the excess of heat produced, and a higher yield interms of both emitted light and generated power. For a massive production of GaN, high-quality epitaxialGaN films with atomically smooth, damage-free surfaces represent a fundamental request. Metalorganicvapor phase epitaxy (MOVPE) is nowadays the most accredited method for a mass production of highquality GaN crystals [1]. In MOVPE, trimethylgallium (TMG) and ammonia are the typical gas-phaseprecursors carried to the growth section by a carrier gas, H2 or N2. Hence, a detailed knowledge of thegrowth mechanism under H2 carrier gas conditions is highly desirable. Kusaba and coworkers reportedthat the growing surface under H2 carrier gas condition is the 3Ga–H surface. In this presentation, we makeuse of first-principles calculations as implemented in our real space density functional theory (RSDFT)package, to shed some light on the step edge structure of GaN under H2 carrier gas condition .