The novel concept of “impurity engineering in CZochralski (CZ) silicon ” for large scaled integrated circuits has been reviewed. By doping with a certain impurities into CZ silicon materials intentionally, such as nitrogen (N), germanium (Ge) and even carbon (C, with high concentration), internal gettering ability of CZ silicon wafers could be improved. Meanwhile, void defects in CZ silicon wafer could be easily eliminated during annealing at higher temperatures. Furthermore, it was also found that the mechanical strength could be increased, so that breakage of wafers decreased. Thus, it is believed that by impurity engineering CZ silicon wafers can satisfy the requirment of ultra large scale integrated circuits.