Influence of substrate temperature on growth of a-Si:H films by reactive facing target sputtering deposition

Hydrogenated amorphous silicon (a-Si:H) films were deposited by reactive facing target sputtering (FTS) technique with a mixture of Ar and H 2 reaction gas. Fourier transform infrared (FTIR) absorption, Raman scattering and ultraviolet-visible optical absorption are used to investigate the microstructure and optical properties of the deposited films. The decrease of the concentration of bonded hydrogen, especially that of (Si-H 2 ) n with increasing substrate temperature ( Ts ), was observed in FTIR spectra, suggesting the atomic density increases and the concentration of microvoids decrease in a-Si:H films. The increase of both the short range order and the intermediate range order of amorphous network for a-Si:H films were verified by Raman scattering spectra, in which increasing Ts decreasing the band width of TO and the scattering intensity ratio I TA / I TO were obtained. All above results clarify the effect of increasing Ts on the microstructure amelioration for a-Si:H films. The reduction of disordered domains is correlated with the film growing process, where the increased surface diffusion mobility and etching of weak bonds is induced by increasing Ts . Furthermore, analysis of optical absorption indicates that the films with a lower optical band gap and a narrower band edge can be obtained by this FTS technique.