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

We describe the compliant behavior of Ge1−ySny buffer layers grown strain-free on Si(100). Deposition of lattice-mismatched epilayers on these buffers introduces significant strains in both systems. Ge1−x−y′SixSny′ and Ge1−xSix alloys are deposited on these buffers via reactions of designer hydrides to quantify these strains in detail. X-ray analysis reveals that Ge1−x−y′SixSny′∕Ge1−ySny and Ge1−xSix∕Ge1−ySny bilayers adopt strain states which minimize their combined elastic energy, as if the films were decoupled from the substrate. Compliant Ge1−ySny 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.