Comparison of Nickel and Iron Gettering in Cz Silicon Wafers

摘要

Gettering of Ni and Fe in silicon wafers is compared using mainly information from photoluminescence mapping (PLM) at room temperature and graphite-furnace atomic absorption spectroscopy (AAS). Applying PLM for analyzing p/p~+ epi wafers, external gettering of Ni is shown to be effective, contrary to external gettering of Fe. Effective internal gettering of Ni requires a high bulk defect density. Applying AAS for analyzing lightly boron-doped wafers, higher efficiency of internal gettering for Fe is confirmed. For both low-thermal budget and high-thermal budget conditions, efficiency of internal gettering is clearly reduced for Ni as compared to Fe.