THE EFFECTS OF OXYGEN PRECIPITATES ON THE ELECTRICAL-PROPERTIES OF SILVER IMPURITIES IN P-TYPE SILICON

Some characteristics of the silver impurity in silicon with and withou t oxygen precipitates are studied by means of the four-point probe, mi nority carrier lifetime, and infra-red absorption spectroscopy measure ments. The relative effect of varying contents of oxygen precipitate o n the impurity is also investigated. Silver proved to be a donor-type impurity in p-type silicon and its presence led to a reduction, by up to a factor of 21, in the lifetime of the minority carriers by the for mation of deep level traps. While the presence of oxygen precipitate i n the substrate has little or no effect on the donor-type behaviour, i t improved slightly the value of the minority carrier lifetime by gett ering some of the Ag impurities and there appears to be a linear depen dence of the improved lifetime on the quantity of precipitated oxygen.