Synthesis and fine patterning of organic–inorganic composite SiO2–Al2O3 thick films

Organic–inorganic composite SiO2–Al2O3 films have been prepared by sol–gel using methacryloxypropyl trimethoxysilane and aluminum sec-butoxide as the precursors. By introduction of organic groups into the inorganic backbone, the smooth and crack-free films could be readily achieved by a one-step dip-coating process, with the thickness up to 4.6 mm after being post-baked at 200 8C for 2 h. The films presented in an amorphous phase with an acceptable chemical homogeneity. Owing to the formation of chelate rings, the gel films showed a strong photosensitivity to ultraviolet light at 325 nm. The uniform fine patterns of SiO2–Al2O3 thick films could be well defined by ultraviolet light imprinting simply using a mask. These performances of SiO2–Al2O3 films indicate the potential for integrated optical systems