Low‐Temperature Out‐Diffusion of Cu from Silicon Wafers

We investigated low temperature out‐diffusion of Cu impurity from the bulk of p‐ and n‐type silicon wafers after contamination followed by diffusion of Cu into silicon during annealing. We show that Cu impurity in the bulk after low‐temperature out‐diffusion can be measured at the surface by total x‐ray fluorescence and graphite furnace atomic absorption spectroscopy 10¹⁰ atom/cm³. In addition, a benefit of low‐temperature annealing is the removal of Cu contamination from the bulk by surface cleaning. We also find that Cu contamination in the bulk of p‐type Si wafers out‐diffuses at room temperature after removing the surface oxide, but this does not happen in the case of n‐type Si material.