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 mixture of O-2/hexamethyldisiloxane injected in an Ar-fed expanding thermal plasma. In order to increase the film density, a radiofrequency (rf, 13.56 MHz) external substrate biasing was applied during deposition, thus delivering ion bombardment during film growth. Fourier transform infrared spectroscopy shows that the film densification at increasing substrate bias occurs 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 atomic force microscopy measurements, which point out to a decrease in film root mean square roughness by as much as 80% (0.19 nm).