Heteroepitaxy of GaN and related materials with a novel two-flow MOVPE horizontal reactor

The behaviour and role of a GaN buffer layer has been investigated in relation with GaN and InGaN heteroepitaxy using a specially designed two-flow horizontal metalorganic vapour phase epitaxy. It is demonstrated that InGaN layers with improved crystal quality can be obtained when a GaN underlying layer is carefully prepared by a two-step growth process consisting of the growth of a thick GaN intermediate layer (r, = 950°C) prepared on a thin low-temperature GaN buffer (T, = 600°C).