Phase separation due to high temperature annealing of sputtered SiOx layers

SiO x layers with lateral composition gradient (co-layers), formed by co-sputtering in argon plasma from Si and Si0 2 targets, were investigated both before and after high temperature annealing using IR absorption and Raman scattering. For all coordinates we found more oxygen in the co-layers than the oxygen amount in SiO 2 layers sputtered from quartz target only. It was found that the quartz target surface in the plasma heats up and this may result in oxygen and silicon monoxide fluxes. The capture of this additional oxygen by the silicon flux during co-sputtering may be the reason for the excess oxygen in the co-layers. For samples with low silicon content (x>1), upon annealing a complete phase separation of SiO x into SiO 2 and Si takes place. In SiO x films with high Si content some of the silicon is in the crystalline phase even before annealing.