HYDROGEN PASSIVATION OF GRAIN-BOUNDARY DEFECTS IN POLYCRYSTALLINE SILICON THIN-FILMS

The dependence of defect passivation in undoped polycrystalline silico n on hydrogenation conditions (i.e., time and temperature) was examine d. At long hydrogenation times the spin density N(S) saturates. The sa turation value of N(S) depends strongly on the hydrogenation temperatu re. The lowest residual spin density was obtained at 350-degrees-C. Mo del calculations of the time and temperature dependence of the defect passivation suggest that the amount of hydrogen necessary for defect p assivation exceeds the density of grain boundary defects by a factor t hat is significantly larger than unity and which depends on the hydrog enation temperature.