IMPACT OF FE AND CU CONTAMINATION ON THE MINORITY-CARRIER LIFETIME OFSILICON SUBSTRATES

The effects of trace amounts of Fe and Cu in p- and n-type silicon wer e investigated with microwave photoconductance decay and surface photo voltage. The wafers received controlled amounts of surface contaminati on of Fe and Cu that are relevant for ultralarge scale integrated tech nologies. The substrate doping type has a strong impact on the effect of the metallic impurities. Fe, as expected, strongly degrades the min ority carrier lifetime of p-type substrates. On the other hand, the im pact of Fe on n-type silicon at least one enter of magnitude lower tha n on p-type. In contrast, Cu is highly detrimental to n-type material, but has no significant impact on the minority carrier properties of p -type silicon for the contamination levels studied.