A stressed MOS device is provided that includes a silicon substrate, a gate electrode and an epitaxial layer of stress inducing monocrystalline semiconductor material. The silicon substrate is characterized by a monocrystalline silicon lattice constant. The gate electrode overlies a silicon channel region at the surface of the silicon substrate. The epitaxial layer of stress inducing monocrystalline semiconductor material is grown in the silicon substrate. The epitaxial layer of stress inducing monocrystalline semiconductor material has a lattice constant greater than the monocrystalline silicon lattice constant, and extends under the silicon channel region.