Influence of hydrogen and oxygen plasma treatments on grain-boundary defects in polycrystalline silicon

The effects of hydrogen, oxygen, and helium plasma exposures on the grain-boundary defects of polycrystalline silicon (poly-Si) were examined. While a remote hydrogen plasma passivates Si dangling-bonds efficiently no change in the defect density is observed after exposing poly-Si to a remote oxygen plasma. On the other hand, an electron cyclotron resonance oxygen and helium plasma results in a decrease of the spin density. Secondary ion mass spectrometry measurements reveal that both plasma exposures vastly increase the hydrogen content of the samples while the O concentration remains unchanged. The increase of the H concentration is proportional to the number of passivated grain-boundary defects.