Surface photovoltage minority-carrier lifetime/diffusion-length analyses were made of Cu-contaminated samples. It was observed that Cu and Cu-associated defects degraded the minority carrier lifetime more extensively in the case of n-type samples than in that of p-type samples. This was explained by studying Cu-related defect levels, as identified by other deep-level transient spectroscopic studies. In Cu-contaminated p-type material, an optical or thermal activation process significantly degraded the diffusion length. Such a process dissociated Cu-Cu pairs (a weak recombination center in p-type material) and the Cu formed extended substitutional defects; which had a much greater recombination activity.

Detection of copper contamination in silicon by surface photovoltage diffusion length measurements W.B.Henley, D.A.Ramappa, L.Jastrezbski: Applied Physics Letters, 1999, 74[2], 278-80