ATOM DIFFUSION DURING MBE GROWTH ON PATTERNED SUBSTRATE

MBE growth an patterned substrate has been studied by means of transmi ssion electron microscopy (TEM). The surface morphology development du ring the initial stage of epitaxial growth and the lateral epilayer th ickness variation have been studied on a nanometer scale. A diffusion model has been proposed to explain the observed phenomena. Based on th is diffusion model, it is proved that the diffusion length of adatoms on (100) plane can be measured from the cross-sectional shadow image a s well as the cross-sectional TEM images of the grown layers. Again, f rom the diffusion model, it is found that Ga adatoms diffusion length ratio on (115A) over that on (100) can be measured from the GaAs layer thickness variation on (100) and at the intersection between (100) an d (115A). The ratio of Ga adatoms diffusion length on (115A) over that on (100) is reported for the first time. (C) 1998 Elsevier Science B. V. All rights reserved.