In Situ Spectroscopic Ellipsometry Monitoring GaN Nucleation Layer Growth and Annealing Behavior in MOVPE

In-situ spectroscopic ellipsometry (SE) was applied to metal-organic vapor phase epitaxial (MOVPE) growth of GaN. The effects of MOVPE reactor pressures on the growth modes of GaN buffer layer were investigated by SE with the assistance of ex-situ scanning electron microscopy (SEM). We further demonstrated the on-line control of the GaN growth mode in MOVPE, which established a feasibility to grow high-quality GaN layers on sapphire substrate at the reactor pressure as low as 20 Torr.