An investigation was made of the low-temperature out-diffusion of Cu from the bulk of p-type and n-type wafers after Cu contamination during annealing. It was shown that Cu impurity in the bulk, after low-temperature out-diffusion, could be measured at the surface by using total X-ray fluorescence and graphite-furnace atomic absorption spectroscopy. A particular benefit of low-temperature annealing was the removal of Cu contamination from the bulk by surface cleaning. It was also noted that Cu contamination in the bulk of p-type wafers out-diffused at room temperature, after removing the surface oxide. This did not happen in the case of n-type material.

M.B.Shabani, T.Yoshimi, H.Abe: Journal of the Electrochemical Society, 1996, 143[6], 2025-30