High‐temperature oxidation resistance of SiO₂‐coated polyimide composite

Silicon dioxide films (500–5,000 Å ‐thick) were deposited on silicon wafers and polyimide composite surfaces by plasma‐enhanced chemical vapor deposition. The chemical reaction takes place on the surface and depends on substrate conditions and process parameters. In the present study, SiO 2 films were deposited from tetraethylorthosilicate (TEOS) in the 275–400°C temperature range under the influence of a radio frequency discharge (13.56 MHz). The properties of the deposited films, such as refractive index, density, stoichiometry, and adhesion, were obtained. The deposition characteristics of the films were studied as a function of process parameters including temperature, pressure, and RF power level. Finally these TEOS‐SiO 2 films were found to be effective in the protection of polyimide‐based composites for higher‐temperature (350–400°C) applications.