Nano-structure in micro-crystalline silicon thin films studied by small-angle X-ray scattering

Hydrogenated micro-crystalline silicon (μc-Si:H) thin films, with similar crystalline volume fraction (Xc) and deposition rate (Rd), were prepared by hot-wire chemical vapor deposition (HWCVD), rf plasma-enhanced CVD (PECVD), plasma-assisted HWCVD (P-HWCVD) and two-step hydrogen dilution (SH) HWCVD. The influence of plasma and two-step SH on nano-structure of μc-Si:H films was studied by using synchrotron radiation small-angle X-ray scattering (SAXS) combined with Fourier transform infrared spectroscopy (FTIR) and flotation density measurement. Compared with the HWCVD sample, the void fraction and mean size of micro-voids were reduced by plasma and two-step SH. The anisotropic growth character was detected in μc-Si:H films.