Continuous GaAs Film Growth on Epitaxial Si Surface in Initial Stage of GaAs/Si Heteroepitaxy

Improvements in the initial stage of GaAs growth on the epitaxial silicon surface without high-temperature Si surface treatment and in the GaAs-Si interface have been observed for the first time by transmission electron microscopy (TEM). Plan-view and cross-sectional TEM images show that initial GaAs layers (10-nm-thick GaAs layer grown at 400°C) on Si continuously cover the whole Si surface. We also observed dislocations in 100-nm-thick GaAs layers grown at 650°C after 400°C growth. The number of dislocations was considerably less than that in conventional thermally treated mechanochemically polished Si samples. These observations show that the epitaxial Si surface has the effect of improving the initial stage of GaAs growth on Si as well as the GaAs-Si interface.