Staged development of modified silicon dioxide films

The hydrolytic generation of SiO2 films from chlorosilanes or alkoxysilanes is interrupted by incorporating labile organic groups which stop SiO2 formation at a processable prepolymer stage. The monomers for the prepolymer have electron withdrawing substituents in the beta-position. The organic groups are removed from the prepolymer at low temperature, extruding ethylene. The formation of SiO2 proceeds by intramolecular condensation of the electronegative substituents which are now in a hydrolytically unstable bond with silicon and hydroxyl groups or ambient moisture. Films of the prepolymer spun onto silicon wafers are converted into uniform SiO2-rich films at temperatures between 150-400 degrees C.