Compliant tin-based buffers for the growth of defect-free strained heterostructures on silicon

We describe the compliant behavior of Ge _1-ySn _y buffer layers grown strain-free on Si(100). Deposition of lattice-mismatched epilayers on these buffers introduces significant strains in both systems. G _1-x-y′, Si _xSn _y′ and Ge _1-xSi _x alloys are deposited on these buffers via reactions of designer hydrides to quantify these strains in detail. X-ray analysis reveals that. Ge _1-x-y′/Ge _1-ySny′/Ge _1-y Sn _y and Ge _1-xSi _x/Ge _1-ySn _y bilayers adopt strain states which minimize their combined elastic energy, as if the films were decoupled from the substrate. Compliant Ge _1-ySn _y buffers thereby enable growth of highly mismatched Ge-rich semiconductors on Si and thus facilitate the long-sought on-chip integration of micro- and optoelectronic functions.