A selectively strained MOS device such as selectively strained PMOS device making up an NMOS and PMOS device pair without affecting a strain in the NMOS device the method including providing a semiconductor substrate comprising a lower semiconductor region, an insulator region overlying the lower semiconductor region and an upper semiconductor region overlying the insulator region; patterning the upper semiconductor region and insulator region to form a MOS active region; forming an MOS device comprising a gate structure and a channel region on the MOS active region; and, carrying out an oxidation process to oxidize a portion of the upper semiconductor region to produce a strain in the channel region.