GaN Growth with Low-Temperature GaN Buffer Layers Directly on Si(111) by Hydride Vapour Phase Epitaxy

GaN films are grown on Si(111) with low-temperature GaN (LT-GaN) layers as buffer layers by hydride vapour phase epitaxy (HVPE). The deposition temperature of the LT-GaN layers is changed from 400 to 900°C. When the LT-GaN layer is deposited at 600°C, GaN films show only c-oriented GaN (0002) and have the band edge emission at 365nm with no yellow luminescence bands. The results indicate that the LT-GaN layer can effectively block the unexpected Si etching by reactive gas during the GaN growth. However, the surface roughness of these GaN films grown on Si(111) is larger than that of GaN films on c-plane sapphire.