Abstract: A method is provided in which an n-type field effect transistor (NFET) and a p-type field effect transistor (PFET) each have a channel region disposed in a first single-crystal semiconductor region having a first composition. A stress is applied at a first magnitude to a channel region of the PFET but not at that magnitude to the channel region of the NFET. The stress is applied by a single-crystal semiconductor layer having a second composition such that the single-crystal semiconductor layer is lattice-mismatched to the first region. The semiconductor layer is formed over the source and drain regions and optionally over the extension regions of the PFET at a first distance from the channel region of the PFET and is formed over the source and drain regions of the NFET at a second, greater distance from the channel region of the NFET, or the semiconductor layer having the second composition is not formed at all in the NFET.