A thin blanket epitaxial layer of SiGe is grown on a silicon substrate to
have a biaxial compressive stress in the growth plane. A thin epitaxial
layer of silicon is deposited on the SiGe layer, with the SiGe layer
having a thickness less than its critical thicknesses. Shallow trenches
are subsequently fabricated through the epitaxial layers, so that the
strain energy is redistributed such that the compressive strain in the
SiGe layer is partially relaxed elastically and a degree of tensile
strain is induced to the neighboring layers of silicon. Because this
process for inducing tensile strain in a silicon over-layer is elastic in
nature, the desired strain may be achieved without formation of misfit
dislocations.