Remote plasma deposited silicon dioxide-like film densification by means of RF substrate biasing: film chemistry and morphology

Silicon dioxide-like films were deposited from a mixt. of O2/hexamethyldisiloxane injected in an Ar-fed expanding thermal plasma. In order to increase the film d., a radiofrequency (rf, 13.56 MHz) external substrate biasing was applied during deposition, thus delivering ion bombardment during film growth. Fourier transform IR spectroscopy shows that the film densification at increasing substrate bias occurs via condensation of silanol groups to form Si-O-Si bridges, accompanied by a decrease of the disorder in the film network. Ion bombardment leads also to the smoothening of film surface as quantified by at. force microscopy measurements, which point out to a decrease in film root mean square roughness by as much as 80% (0.19 nm). [on SciFinder (R)]