Ultraviolet induced transformation of polysiloxane films

We have studied the transformation of a polysiloxane film induced by high temperature annealing and by 248 and 193 nm excimer laser irradiation. Auger electron and x-ray photoelectron spectroscopy have been used to study the Si, O, and C profiles and the Si-O valence band structure before and after transformation. We suggest that laser induced transformation results from localized heating and oxidation of the Si-O chains coupled with a breakdown and oxidation of previously attached benzene groups into volatile gaseous products which diffuse out of the film.