Direct deposition of silica films using silicon alkoxide solution

Dense silica films were directly deposited on a substrate in basic solution s (similar to pH 11) of tetraethoxysilane (TEOS) at temperatures <60 degree s C. The film formation was observed through heterogeneous nucleation on a hydrophilic surface with the intermediate condition between gel formation a nd stable solution. The refractive index, the OH content and the hardness i ndicate that the structure of the deposited films are similar to that of so l-gel silica films calcined at 500 degrees C. We suggest that the growth an d the densification of the films occur simultaneously during the deposition in the solutions. (C) 1998 Elsevier Science B.V. All rights reserved.