ELECTRICAL-PROPERTIES OF SILVER IMPURITIES AND THEIR ANNEALING BEHAVIOR IN P-TYPE FZ SILICON

The electrical activity of silver as well as its annealing properties in 10 Omega cm p-type Fe silicon substrate are studied by means of the four-point probe and minority carrier Lifetime measurements. Silver a tom concentration in the range 10(14) to 10(15) cm(-3) consistently sh owed a donor type behaviour in the material and its presence led to a reduction of up to two orders of magnitude in the lifetime of minority carriers by the formation of deep-level traps. Isochronal annealing o f silver contaminated specimens showed some gettering of the Ag impuri ties with resulting temperature dependent changes in the resistivity a s well as the minority carrier lifetime values. Analysis of our result s shows that a large fraction of the silver impurity atoms present for ms the deep level defects and both the deep- and donor-levels appear t o originate from the same source.