Mismatched Heteroepitaxy of Tetrahedral Semiconductors with Si via ZrB2 Templates

Abstract

We demonstrate integration of cubic SiC (heterostructures and nanostructures) and assemblies of Ge nanoscale islands with Si substrates via a conductive and reflective ZrB2 buffer layer. Hexagonal ZrB2 is grown on cubic Si(111) via a coincidence-misfit mechanism in which the strain is accommodated by edge dislocations along the interface. Ge islands with uniform sizes and strain-free microstructures were grown on ZrB2/Si(111) at 500 °C via thermolysis of Ge2H6, circumventing the strain-driven (Stranski−Krastanov) island formation on Si and associated limitations. Heteroepitaxy between ZrB2(0001) and Ge(111) is obtained via alignment of four lattice rows of Ge with every five rows of ZrB2, (i.e., “magic mismatch”) despite the large difference in lattice constants. Cubic SiC layers with monocrystalline microstructures and atomically abrupt interfaces are grown on ZrB2/Si(111) via single source molecular beam epitaxy of C2(SiH3)2 at 800 °C. Nanoscale SiC islands with perfectly coherent zinc blende structures...