Effects of ion beam irradiation on the properties and epitaxial growth of aluminium nitride film by the ion beam assisted deposition process

Abstract

Aluminium nitride thin films were grown on Si(111) substrates by ion beam assisted deposition. Epitaxial growth of the AIN films was obtained at the low temperature of 450 °C. Characterization of the AIN epitaxial layer was carried out by grazing-incidence diffraction (GID) and high resolution transmission electron microscopy (HRTEM). GID analysis showed two kinds of epitaxial orientation between AIN epitaxial layer and Si substrate. An amorphous layer was observed at the interface between AIN film and Si by cross-sectional HRTEM analysis. The amorphous layer could release the misfit strain between the AIN film and the Si substrate in an early stage of growth. The AIN epitaxial layer formed despite the large lattice mismatch. In addition, the optical properties of AIN films including transmittance, energy band gap, and refractive index were determined and discussed.