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A method for producing a thin-film transistor by using a crystalline silicon film that has been formed by using nickel as a metal element for accelerating crystallization of silicon. In forming source and drain regions, phosphorus as an element for gettering nickel is introduced therein by ion implantation. Nickel gettering is effected by annealing. For example, in the case of producing a P-channel thin-film transistor, both phosphorus and boron are used. Boron determines a conductivity type, and phosphorus is used as a gettering material.