A semiconductor device comprises a field-effect transistor arranged in a semiconductor substrate, which transistor has a gate electrode, source/drain impurity diffusion regions, and carbon layers surrounding the source/drain impurity diffusion regions. Each of the carbon layers is provided at an associated of the source/drain impurity diffusion regions and positioned so as to be offset from the front edge of a source/drain extension in direction away from the gate electrode and to surround as profile the associated source/drain impurity diffusion region.