Silicon molecular beam epitaxy on gallium arsenide

Abstract
Si overlayers have been grown under ultrahigh vacuum conditions on GaAs (100) single crystals by means of molecular beam epitaxy. For growth temperatures above 400 °C (2×1) low-energy electron diffraction patterns of the Si overlayers were observed at all film thicknesses produced (1–5000 Å). By means of Auger electron spectroscopy it was found that the surface of the grown Si was enriched with As and Ga. Two different mechanisms contribute to the enrichment and lead to a high (∼1018/cm3) background doping level. With Rutherford backscattering using ion channeling it was found that there is considerable lattice disorder at the Si-GaAs interface, although the crystal quality of the Si improves markedly towards the Si surface for thicker layers where the minimum channeling yield drops to 9%. With medium energy ion scattering it was established that no island formation occurs during initial stages of the growth.