Effect of hydrogen on the surface-diffusion length of Ga adatoms during molecular-beam epitaxy

Abstract

Systematic measurements were carried out on the surface‐diffusion length of Ga adatoms during the molecular‐beam epitaxy of GaAs in the presence of hydrogen atoms (H⋅) or hydrogen molecules (H₂). The spatial variation of the growth rate on the (100) surface adjacent to the (111)A surface was measured from the period of the reflection high‐energy electron diffraction (RHEED) intensity oscillations using in situ scanning microprobe RHEED. The surface‐diffusion length of Ga adatoms, which was derived from the spatial variation of the growth rate, becomes larger along with an increase in the H⋅ or H₂ pressure. It also increases as the substrate temperature is raised under H⋅ or H₂ pressure. The diffusion length in the case of H⋅ introduction is larger than that in the case of H₂ introduction.