Hydrogen passivation of grain boundary defects in polycrystalline silicon thin films

Abstract

The dependence of defect passivation in undoped polycrystalline silicon on hydrogenation conditions (i.e., time and temperature) was examined. At long hydrogenation times the spin density NS saturates. The saturation value of NS depends strongly on the hydrogenation temperature. The lowest residual spin density was obtained at 350 °C. Model calculations of the time and temperature dependence of the defect passivation suggest that the amount of hydrogen necessary for defect passivation exceeds the density of grain boundary defects by a factor that is significantly larger than unity and which depends on the hydrogenation temperature.