Structural and morphological properties of evaporated SiOx films

SiOx films with thickness ranging from 50 nm to several micrometres were ev aporated on crystalline Si at different O-2 pressures. The stress of these films, evaluated by profilometer measurements, is tensile and increases wit h increasing O-2 pressure. Atomic force microscopy data show a quite smooth surface of the SiOx films, with a rms roughness less than 1 nm for all fil m deposited at low O-2 pressures. The growth in a reactive atmosphere incre ases the roughness to 1.5 nm and changes strongly the film morphology. Surf ace morphology also evolves on the thickness, following a dynamic growth mo del with negligible surface diffusion. The chemical composition and the inn er structure were investigated by Raman spectroscopy.