SI SUBSTRATE PREPARATION FOR GAAS SI BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

The effects of pre-growth treatments on Si substrates on the quality of GaAs epilayer have been studied by MOCVD. GaAs layers were grown on Si substrates tilted 2° toward the [011] direction using a two step growth method. All GaAs epilayers grown were single domain, although two crystallographic orientations with respect to the tilted direction were detected depending on the pre-growth and/or growth conditions. Crystallographic orientation is interchanged depending on the temperature and time of the AsH3 preflow and the V/III ratio. Furthermore, the crystallinity of GaAs on Si is poor for an AsH3 preflow temperature above 650°C, in comparison with those below 650°C. The crystallinity of GaAs on Si is independent of the crystallographic orientation. © 1990.