Influence of the deposition parameters on the electronic and structural properties of pulsed laser ablation prepared Si1-xCx thin films

Si1−xCx thin films have been deposited by pulsed laser ablation of a polycrystalline silicon carbide target in vacuum. The influence of the deposition parameters on the optical and structural properties of the samples was investigated by means of Fourier transform IR, Raman, ex situ ellipsometric, x-ray photoelectron, and x-ray absorption near edge structure spectroscopies. Both deposition temperature and laser fluence were increased up to 1150 K and 14 J /cm2, respectively. Increasing the two parameters, a better quality of the thin films was observed due to the existence of a crystalline order on a nanometric scale. Nevertheless, at higher deposition temperatures, a graphitic phase occurred inducing a degradation of the optical properties. Such a phase was not observed increasing the laser fluence. The film formation mechanism has also been qualitatively discussed on the basis of the subplantation model proposed by Lifshitz et al. Phys. Rev. Lett. 62, 1290 1989; Phys. Rev. B 41, 1046 1990.