A semiconductor device having at least one transistor covered by an ultra-stressor layer, and method for fabricating such a device. In an NMOS device, the ultra-stressor layer includes a tensile stress film over the source and drain regions, and a compressive stress film over the poly region. In a PMOS device, the ultra-stressor layer includes a compressive stress film over the source and drain regions and a tensile stress film over the poly region. In a preferred embodiment, the semiconductor device includes a PMOS transistor and an NMOS transistor forming a CMOS device and covered with an ultra stressor layer.