A method for producing a semiconductor integrated circuit device having field effect transistors, comprising the step of forming a parent body layer having the shape of a gate electrode pattern made of a silicon film on the surface of a device formation area of a silicon substrate through a gate insulating film and then froming a pair of semiconductor areas as source and drain regions in a surface layer portion of the device formation area of the silicon substrate, the step of forming an amorphous layer by implanting ions of a Group IV element heavier than silicon into the surface layer portion of the parent body layer and into the surface layer portion of the semiconductor area, and the step of forming a high melting metal film on the surface of the silicon substrate inclusive of the surface of the amorphous layer, applying then the first heat-treatment to form a silicide layer, removing selectively the high melting metal film and thereafter applying the second heat-treatment to activate the silicide layer. Ion implantation of a Group IV element heavier than silicon is effected in an energy quantity such that the range of the implanted ion is greater than the thickness of the high melting metal film. Ion implantation of the Group IV element heavier than silicon is effected in a dose in the range of 1x10 [atoms/cm ] to 1x10 [atoms/cm ].