Surface Segregation and Composition Fluctuations in ammonia MBE and MOVPE of InGaN

Abstract

ABSTRACTSurface segregation and phase separation are investigated as processes limiting the indium incorporation in InGaN grown by ammonia Molecular Beam Epitaxy (MBE) and Metal- Organic Vapor Phase Epitaxy (MOVPE). It is shown that a significant concentration of indium on the growing surface may prevent the adsorption of ammonia via site blocking mechanism and result in appearance of In droplets instead of InGaN growth. Another conclusion is that the composition fluctuations in InGaN are related to coexistence of strained and relaxed InGaN islands rather than to the phase separation as commonly assumed.