Reaction Kinetics of GaN Metal-Organic Vapor-Phase Epitaxy Analyzed by Multi-Scale Profiles of Growth Rate

Abstract

The growth mechanism and rate constants of GaN metal-organic vapor-phase epitaxy (MOVPE) have been unclear in spite of the necessity for large-scale production of this material. In this work, the major precursor of GaN has been deduced and its surface reaction rate constant has been obtained through the analysis of multi-scale growth-rate profiles both in the reactor-scale and in the micrometer-scale profiles that were obtained by selective-area growth. Usually, it is difficult to explore surface reaction kinetics, especially for the MOVPE of GaN, because of mass-transfer-limited kinetics. This multi-scale analysis, however, has clarified that a single precursor, the gas-phase reaction product between (CH3)3Ga and NH3, leads to the growth of GaN with a surface reaction probability of approximately 0.4 at 1400 K which is a typical growth temperature. A lumped reaction model of GaN MOVPE was proposed that led to reasonable agreement between the simulated growth-rate profile in the reactor-scale and the corresponding measured profile.