SUBSTRATE-TEMPERATURE DEPENDENCE OF SIH CONCENTRATION IN SILANE PLASMAS FOR AMORPHOUS-SILICON FILM DEPOSITION

Spatial distributions of SiH radicals were measured between capacitively coupled electrodes for various substrate temperatures (T//s equals 20-300 degree C) in RF glow discharges of pure silane. Laser-induced fluorescence and optical emission spectroscopic techniques were applied to determine the relative SiH concentrations in the ground state and in the excited state respectively. Both concentrations increase near the substrate with increasing substrate temperature T//s. In their respective Arrhenius plots, the concentrations increase slowly for T//s less than 180 degree C and grow rapidly for T//s greater than 180 degree C. The increase in SiH concentrations for T//s greater than 180 degree C is due to the increase in current density of fast electrons which are responsible for gas ionization and silane dissociation.