Hydrogen ion-implantation induced gettering effects in polycrystalline silicon

This paper reports the gettering effects in pollycrystalline silicon induced by hydrogen ion implantation. As-ion implanted polycrystalline silicon wafers exhibited slightly lower lifetime than the virgin wafers, primarily due to the damage introduced by the ion-implantation. Annealing the sample at temperatures of 850 degrees C drove all hydrogen from the sample but left a band of defects and microvoids located about 0.7 mu m beneath the surface. These defects and microvoids acted as sinks for metal impurities and defect accumulation. Both life time measurement and solar cell performance showed that the polycrystalline silicon treated with hydrogen ion implantation had better minority carrier lifetime and cell performance than virgin samples.