Electric degradation of silicon wafer due to Cu, Fe, and Ni contamination has been studied using MCZ with low oxygen and CZ wafers. In the cases of Cu and Ni contamination, the electric properties depended on the characteristics of the starting wafers,. especially the type of conductance. The behavior of these metals in the low temperature region played an important role to understand the electric properties. On the contrary, no difference between p- and n-type wafers was observed in Fe contamination in our experiment.
The surface defects were observed with high density in the MCZ wafers in Cu contamination. These defects were sensitive to the degradation of the MOS C-t generation lifetime. Making use of this relation, the efficiency of the extrinsic gettering was evaluated.