A silicon wafer is produced through the steps of forming a silicon ingot by a CZ method with an interstitial oxygen concentration of not more than 7.0×1017 atoms/cm3 and with a diameter of a COP occurring region not more than a diameter of a crystal, slicing a wafer from the silicon ingot after doping the silicon ingot with phosphorus, forming a polysilicon layer or a strained layer on one main surface of the wafer, and mirror polishing the other main surface of the wafer.