GaAs growth mechanisms of exact and misoriented {001} faces by the chloride method in H-2: Surface diffusion, spiral growth, HCl and GaCl3 desorption mechanisms

A general theoretical model of the {001}GaAs growth has been developed to understand the different processes involved in the AsCl3/H-2 and AsCl3/He systems. The step flow and spiral growth mechanisms, and the processes of GaCl adsorption and chlorine desorption by H-2 in HCl have been determined by fitting theoretical and experimental curves. A mechanism of GaCl adsorption in a second layer followed by GaCl3 desorption, determined from a fit to experimental results obtained in the AsCl3/He system, explains the increase of the growth rate observed with H-2 at low substrate temperature or at high GaCl molar fraction in the vapor phase. The parameters involved in the growth mechanisms have been calculated by taking into account mass transfert.