Patent ID: 7157354

Claim:
A method for gettering a transition metal impurity diffused in a silicon crystal at ultra high-speeds to form deep impurity levels therein, said method comprising the steps of: codoping two kinds of impurities consisting of oxygen (O) and carbon (C), into silicon at a concentration equal to or greater than that of at least one transition metal impurity selected from the group consisting of Co, Ni and Cu which are released from a raw material during a process of forming a silicon single crystal and mixed in said silicon crystal, and Cu which is mixed in a silicon wafer during a process of printing a Cu wiring; and thermally annealing said impurity-doped silicon by a single heating, the single heating being in a temperature range from 250° C. to 500° C. to form a transition metal-O—C complex comprising an atom of said transition metal impurity, said C and said O, so as to precipitate said impurity complex at an interstitial position in said silicon crystal, whereby said transition metal impurity is confined in said silicon crystal to prevent the ultra high-speed diffusion of said transition metal impurity and electrically deactivate deep impurity levels to be induced by said transition metal impurity.