A semiconductor device of complementary structure with increased carrier mobilities of both polarities by applying orientation-dependent mechanical stresses to their respective semiconductor channel regions, comprises a semiconductor region subjected to compressive stress in a first direction along a surface and tensile stress in a second direction different from the first direction, a field effect transistor of a first conductivity type formed in the semiconductor region and including source and drain regions separately arranged along the first direction and a field effect transistor of a second conductivity type formed in the semiconductor region and including source and drain regions separately arranged along the second direction.