Studies of Group III-Nitride Growth on Silicon

Abstract

ABSTRACTThe growth of Group III-Nitrides on Si substrates offers the possibility of combining optoelectronics with Si technology. We have been studying the growth of Group III-Nitrides on clean and oxidised Si surfaces with a view to local area epitaxy. X-ray data indicates that alloys of (AlGa)N and (InGa)N of controlled composition can be grown on Si using a plasma enhanced Molecular Beam Epitaxy method over the entire composition range from InN to AlN. Films grown on uncleaned, oxidised surfaces of Si are polycrystalline/amorphous in contrast to growth on chemically cleaned Si substrates which show the usual columnar structure common in Group III-Nitrides. XPS studies indicate that there is little tendency for spinodal decomposition, but the In peaks in (InGa)N alloys show that more than one chemical environment is present. The composition of the alloys deduced from electron probe microanalysis studies agree well with those from X-ray measurements, assuming Vegard’s law is valid for both alloy systems.