Influence of hydrogen implantation on the resistivity of polycrystalline silicon

The grain boundary passivation effect in polycrystalline silicon (polysilicon) thin films by hydrogen implantation has been studied. Boron-doped polysilicon was implanted with low-energy ions followed by low-temperature annealing. Resistivity measurements show that the change in resistivity after implantation depends on the boron concentration in polysilicon. At low boron concentration (<1×1019 cm−3), three orders of magnitude decrease in resistivity has been achieved. However, at higher boron concentration (>1×1019 cm−3), the resistivity increased after hydrogen implantation. This increase is ascribed to implant-induced damage which cannot be totally recovered by low-temperature annealing.