Kinetic Analysis Of Surface Adsorption Layer For Ingaasp-related Binary Materials Using In Situ Ras

摘要

Kinetic analysis of the surface adsorption layer on GaAs, InAs, InP, and GaP surfaces during metalorganic vapor phase epitaxy (MOVPE) was performed by in situ monitoring of the temporal behavior of surface reconstructions using reflectance anisotropy spectroscopy (RAS). When the flow of group-Ⅲ sources was switched on/off, the transient RA signal exhibited two time constants t_0 and t, in response to the generation/extinction of the adsorption layer. It was considered that t_0, when the supply of group-Ⅲ sources was started, corresponds to the adsorption of group-Ⅲ atoms from the gas phase to the adsorption layer, and that ti, when the supply of group-Ⅲ sources was terminated, is associated with the incorporation of adsorbed group-Ⅲ atoms to the crystal. The rate constant of adsorption, 1/t_0, was approximately 2s~(-1) for all surfaces except for GaP. The rate constant of incorporation, 1/t_1, ranged from 0.1 to 10s~(-1). It was found that 1/t_1 for the As-containing materials was faster than that for P-related materials, and 1/t_1 for In-containing materials was faster than that for the Ga-containing materials. For the As-containing materials, 1/t_1, agreed with the incorporation rate constants of adsorbed group-Ⅲ precursors obtained using the angmuir-Hinshelwood model by the analysis of selective-area growth (SAG).