The effect of heat treatment on redistribution of fast diffusing impurities in polycrystalline silicon

Abstract

The effect of heat treatment on minority carrier surface recombination velocity in polycrystalline silicon samples has been examined in the temperature range (600–900 °C) using the electron-beam induced-current mode of a scanning electron microscope. Minority carrier trap center density, calculated from minority carrier surface recombination velocity data, varying from 8.9×1011 to 6.37×1013 cm−2 have been measured. A finite variation in the minority carrier trap center density indicates that metallic impurities diffuse to the surface from the bulk of the sample. The activation energy of impurity atom diffusion is found to be 1.1±0.1 eV.