Patent ID: 7727867

Claim:
A method for manufacturing a SIMOX wafer sequentially comprising: heating a wafer to a temperature in the range of 200 to 600° C. and implanting oxygen ions from a surface of a silicon wafer in an ion-implanting device and to form a first ion-implanted layer having a peak oxygen concentration at a depth d 1 from the surface of the wafer; implanting the oxygen ions from the surface of the wafer having the first ion-implanted layer formed therein in the ion-implanting device to form a second ion-implanted layer that is in an amorphous state such that the second ion-implanted layer has a damage peak at a depth d 2 wherein depth d 2 is shallower than depth d 1 and becomes continuous with a surface of the first ion-implanted layer on a front surface side of the wafer; and subjecting the wafer to a high temperature heat treatment in a furnace in an atmosphere containing oxygen wherein the temperature is elevated to not lower than 1300° C. but lower than the melting point of silicon to change the first and the second ion-implanted layers into a BOX layer, wherein an oxygen ion dose amount for formation of the first ion-implanted layer is 1.25 to 1.5×10 17 atoms/cm 2 , an oxygen ion dose amount for formation of the second ion-implanted layer is 1.0×10 14 to 1.0×10 16 atoms/cm 2 , the wafer is preheated to a temperature to at least 50° C. but lower than 200° C. before forming the second ion-implanted layer, and the second ion-implanted layer is formed while continuously heating the wafer to the preheating temperature and wherein a plurality of wafers having only the first and second ion implantation layers formed therein are sequentially, one by one, removed from the ion implanting device and cleaned, dried and subjected to the high temperature heat treatment in a heat treatment furnace comprising: elevating a temperature from 1320 to 1350° C. in an atmosphere containing an inert gas and oxygen of 0 to 5.0 volume %, holding the elevated temperature for 6 to 36 hours in an atmosphere containing a mixture of an inert as and oxygen of 10.0 to 50.0 volume %; and cooling the wafer to room temperature.