Annealing effect on the resistivity of polycrystalline silicon films passivated with plasma-deposited silicon-nitride films

The thermal annealing effect on resistivity is investigated for polycrystalline silicon films passivated with plasma-enhanced chemically vapor deposited silicon-nitride (p-SiN) films. The resistivity in the heavily doped polycrystalline silicon films has a minimum value at an annealing temperature of approximately 500 °C, and the resistivity in the lightly doped films monotonically increases with the increase of annealing temperature. The dependence of the resistivity on annealing temperature is explained in terms of the variations of the density and the energy level of the traps at the grain boundaries, which are caused by the adsorption or the decomposition of hydrogen atoms. These conclusions are obtained by comparing the dependence in the polycrystalline silicon films with p-SiN films with that in the plasma-hydrogenated polycrystalline silicon films without p-SiN films.