Characterization of doped hydrogenated nanocrystalline silicon films prepared by plasma enhanced chemical vapour deposition

The B- and P-doped hydrogenated nanocrystalline silicon films (nc-Si:H) are prepared by plasma-enhanced chemical vapour deposition (PECVD). The microstructures of doped nc-Si:H films are carefully and systematically characterized by using high resolution electron microscopy (HREM), Raman scattering, x-ray diffraction (XRD), Auger electron spectroscopy (AES), and resonant nucleus reaction (RNR). The results show that as the doping concentration of PH₃ increases, the average grain size (d) tends to decrease and the crystalline volume percentage (X_c) increases simultaneously. For the B-doped samples, as the doping concentration of B₂H₆ increases, no obvious change in the value of d is observed, but the value of X_c is found to decrease. This is especially apparent in the case of heavy B₂H₂ doped samples, where the films change from nanocrystalline to amorphous.