An embodiment includes a device comprising: a first epitaxial layer, coupled to a substrate, having a first lattice constant; a second epitaxial layer, on the first layer, having a second lattice constant; a third epitaxial layer, contacting an upper surface of the second layer, having a third lattice constant unequal to the second lattice constant; and an epitaxial device layer, on the third layer, including a channel region; wherein (a) the first layer is relaxed and includes defects, (b) the second layer is compressive strained and the third layer is tensile strained, and (c) the first, second, third, and device layers are all included in a trench. Other embodiments are described herein.