Competitive Kinetics Model to Explain Surface Segregation of Indium during InGaP Growth by Using Metal Organic Vapor Phase Epitaxy

Abstract

An InGaP layer grown by metal organic vapor phase epitaxy (MOVPE) often has an In-rich region within ∼5 nm from the top of the layer. This surface segregation degrades the interface abruptness of InGaP/GaAs systems, which is attractive for high-performance devices such as high electron mobility transistors (HEMTs). This segregation in lattice-matched InGaP/GaAs systems can be explained by considering a “subsurface” in which a surface adsorption layer controls the composition of grown epitaxial layers. In this study, the existence of a subsurface during MOVPE growth of InGaP was experimentally confirmed through kinetic analysis involving a flow modulation method. The kinetic parameters of a subsurface model, such as adsorption and desorption rate constants of each species, were estimated based on experimental data obtained from flow modulation, and then used to successfully explain the In surface segregation in InGaP-MOVPE.