Channel backscattering characteristics of strained PMOSFETs with embedded SiGe source/drain

Channel backscattering ratios of PMOSFETs with various embedded SiGe source/drain structures are analyzed in terms of the scattering theory. We found that both the backscattering ratio and injection velocity are greatly influenced by the location and recess depth of SiGe source/drain. Although the strain-enhanced injection velocity is beneficial to the current gain, the accompanying backscattering ratio increase adversely impacts the overall performance, and therefore a trade-off exists between injection velocity and backscattering ratio during the optimization of such strain technique. The mechanism of increased backscattering ratio under uniaxial compressive strain is also investigated