PURPOSE: To restrain that the drain current of a transistor is dropped by preventing that the contact resistance of a silicide with a semiconductor diffused layer is increased.

CONSTITUTION: After the junction of a semiconductor diffused layer 3 has been formed and before a silicide layer is formed, an impurity concentration is increased by implanting ions 6 additionally in such a way that the peak of a concentration is situated near a part where the bottom of the silicide layer is positioned. Thereby, even when the silicide layer is formed and the silicide layer sucks out impurities in the semiconductor diffused layer, it is possible to prevent that a contact resistance is increased without making a Schottky barrier high because the impurity concentration has been increased in advance.