Effect of Higher-Order Silane Deposition on Spatial Profile of Si-H2/Si-H Bond Density Ratio of a-Si:H Films
Liu SHI, Kazuma TANAKA, Hisayuki HARA, Shota NAGAISHI, Daisuke YAMASHITA, Kunihiro KAMATAKI, Naho ITAGAKI, Kazunori KOGA, Masaharu SHIRATANI
Plasma and Fusion Research
We studied how the deposition of SiH3 radicals, higher-order silane molecules, and clusters contributed to the bond configuration of hydrogenated amorphous silicon (a-Si:H) films. In our experiment, the deposition of three species was controlled using a multi-hollow discharge plasma chemical vapor deposition (MHDPCVD) method using a cluster-eliminating filter. We reduced the incorporation of higher-order silane (HOS) molecules into the films by increasing the gas flow velocity in the hollows from 1008 to 2646 cm/s. The results show that the lower incorporation of HOS molecules into the films reduced the SiH2/SiH bond ratio, i.e., ISiH2/ISiH. Moreover,two-dimensional profiles of the ISiH2/ISiH ratio and the surface morphology suggest that the surface migration of HOS molecules is similar to that of the SiH3 radicals, and the ISiH2/ISiH ratio is localized by the deposition of HOS molecules. Moreover, the results of optical emission spectroscopy show that HOS radical generation is irrelevant to the gas flow velocity.
a-Si:H films, SiH2/SiH bond density ratio, plasma CVD, Raman spectroscopy, microscopic FTIR