Modification of grain boundaries in polycrystalline silicon with fluorine and oxygen

Hydrogen plasmas have been shown to significantly reduce barrier heights and recombination center densities in the grain boundaries in polycrystalline silicon. These results have stimulated interest in the use of other modifying agents. We demonstrate here that the exposure of n-type polycrystalline silicon to fluorine and oxygen in molecular and atomic forms can result in increased potential barrier heights. This has implications for the development of silicon varistors and capacitors for use in integrated circuits.