A first dielectric layer is formed over a PFET gate and an NFET gate, and lithographically patterned to expose a PFET area, while covering an NFET area. Exposed PFET active area is etched and refilled with a SiGe alloy, which applies a uniaxial compressive stress to a PFET channel. A second dielectric layer is formed over the PFET gate and the NFET gate, and lithographically patterned to expose the NFET area, while covering the PFET area. Exposed NFET active area is etched and refilled with a silicon-carbon alloy, which applies a uniaxial tensile stress to an NFET channel. Dopants may be introduced into the SiGe and silicon-carbon regions by in-situ doping or by ion implantation.