Silicon oxycarbide thin films deposited from viniltrimethoxysilane ion beams

Reactive ion beam synthesis of silicon oxycarbide (a-SiCO:H) thin films was carried out by the viniltrimethoxysilane ion beams. An ion source with cold cathode and closed drift of electrons was used. The average energy and intensity of ion beams were equal to 100∼550 eV and 0.05∼2 mA/cm2, respectively. A Fourier transform infrared spectroscopy (FTIR), an ultraviolet and a visible optical absorption spectra, and ellipsometry measurements were obtained for the thin films. The effect of the annealing in argon at 1050 °C on the FTIR spectra was also investigated. The FTIR spectra analysis indicated that Si-C, Si-O-Si and Si-H bonds were presented in the films and that the annealing resulted in removing of Si-H bonds (around 870 cm− 1) from the films while the peak intensity of Si-C and Si-O-Si bonds increased. Following the increase of energy and intensity of the ion beam the optical band gap Eg widened from 1.9 up to 2.4 eV and the refractive index n was increased from 1.8 up to 2.4. These changes of the film optical properties are caused by the condensation of the film structure resulting from the increase of Si-C bond content.