A method and apparatus is presented that provides mobility enhancement in the channel region of a transistor. In one embodiment, a channel region (18) is formed over a substrate that is bi-axially stressed. Source (30) and drain (32) regions are formed over the substrate. The source and drain regions provide an additional uni-axial stress to the bi-axially stressed channel region. The uni-axial stress and the bi-axially stress are both compressive for P-channel transistors and tensile for N-channel transistors. Both transistor types can be included on the same integrated circuit.