Effects of hydrogen in AlAs growth by atomic hydrogen-assisted molecular beam epitaxy

摘要

The transition temperature T_c for the AlAs growth to change from/to a nucleation mode and step-flow mode have been studied on vicinal GaAs substrates (A-surface and B-surface) in molecular beam epitaxy (MBE) and atomic hydrogen-assisted MBE (H-MBE) using reflection high-energy electron diffraction (RHEED). THe lowering of T_c was clearly observed in H-MBE compared to conventional MBE. For growth of AlAs on vicinal GaAs substrate in H-MBE, atomic H is thought to promote not only the re-evaporation of Al adatoms ont he terrace, but also the incorporation of Al at the step edges, thesreby facilitating a step-flow growth mode at a lower temperature than in MBE. The differences in the fundamental growth mode between on A-surface and B-surface have also been studies based on the differences in the atomic structure between the two substrates.