Low Temperature Epitaxial Growth of AlN & GaN Thin Films by the Method of Ion Beam Assisted Deposition

ABSTRACTThe epitaxial layers of AIN and GaN were grown on Si and Sapphire substrate at a relatively low temperature of around 500 °C using the process of reactive ion beam assisted deposition. The optimum ion beam energy for epitaxial growth of AIN and GaN films was found to be about 50 eV. Characterization of the epitaxial layers was carried out by GID (Grazing-Incidence x-ray Diffraction) and high resolution TEM observation. The orientational relations between epitaxial layer and substrate were determined through these analysis. Very thin amorphous layers were observed at the interfaces of bom AIN and GaN films grown on Si(111) substrate, whereas the films grown on Sapphire substrate has no amorphous layer. The amorphous layer may act as a buffer layer enabling the growth of the epitaxial layers of AIN and GaN by relaxing the misfit strain in the early growing stage.