NFET and PFET devices with separately strained channel regions, and methods of their fabrication is disclosed. A stressing layer overlays the device in a manner that the stressing layer is non-conformal with respect the gate. The non-conformality of the stressing layer increases the amount of stress that is imparted onto the channel of the device, in comparison to stressing layers which are conformal. The method for overlaying in a non-conformal manner includes non-conformal deposition techniques, as well as, conformal depositions where subsequently the layer is turned into a non-conformal one by etching.