Structural and morphological properties of evaporated SiOx films

SiO x films with thickness ranging from 50 nm to several micrometres were evaporated on crystalline Si at difTerent O2 pressures. The stress of these films, evaluated by profilometer measurements, is tensile and increases with increasing O2 pressure. Atomie force microscopy data show a quite smooth surface of the SiO x films, with a rms roughness less than 1 nm for all film deposited at low O2 pressures. The growth in a reactive atmosphere increases the roughness to 1.5 nm and changes strongly the film morphology. Surface morphology also evolves on the thickness, following a dynamie growth model with negligible surface diffusion. The chemical composition and the inner structure were investigated by Raman spectroscopy.