The present invention provides a strained-Si structure, in which the nFET regions of the structure are strained in tension and the pFET regions of the structure are strained in compression. Broadly the strained-Si structure comprises a substrate; a first layered stack atop the substrate, the first layered stack comprising a compressive dielectric layer atop the substrate and a first semiconducting layer atop the compressive dielectric layer, wherein the compressive dielectric layer transfers tensile stresses to the first semiconducting layer; and a second layered stack atop the substrate, the second layered stack comprising an tensile dielectric layer atop the substrate and a second semiconducting layer atop the tensile dielectric layer, wherein the tensile dielectric layer transfers compressive stresses to the second semiconducting layer. The tensile dielectric layer and the compressive dielectric layer preferably comprise nitride, such as Si.sub.3N.sub.4.