Deposition of Plasma-Polymerized Styrene under Ion Bombardment

Abstract

Ion bombardment on a growing film is an effective way to modify film properties. In this study, plasma polymerized styrene thin films are deposited on silicon wafers, glass plates, and polyimide films under varying degrees of ion bombardment in a 13.56 MHz, asymmetric plasma reactor. The degree of ion bombardment is varied by adjusting the power and pressure. FTIR spectra of the deposited films show that sp 2 fraction and hydrogen concentration decrease with increasing ion bombardment on the substrate. RBS data show that the atomic fraction of carbon is uniform throughout the film. Film adhesion is very poor above -325 V of substrate bias voltage at pressure of 70 mTorr. At lower substrate bias voltages, NH 4 OH cleaning enhances the adhesion of the film on silicon substrates, whereas higher substrate temperature gives better adhesion on glass plates.