EFFECT OF HYDROGEN ON THE SURFACE-DIFFUSION LENGTH OF GA ADATOMS DURING MOLECULAR-BEAM EPITAXY

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 (H-2). 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 H-2 pressure. It also increases as the substrate temperature is raised under H. or H-2 pressure. The diffusion length in the case of H. introduction is larger than that in the case of H-2 introduction. (C) 1995 American Institute of Physics.