Low temperature chemical vapor deposition of Si-based compounds via SiH ₃SiH ₂SiH ₃: Metastable SiSn/GeSn/Si(100) heteroepitaxial structures

Growth of Si1-x Snx alloys on Ge1-y Sny -buffered Si(100) was achieved via reactions of Sn D4 and Si H3 Si H2 Si H3 at 275 °C. Kinetic studies indicate that unprecedented low growth temperatures are made possible by the highly reactive Si H2 groups. The authors obtain supersaturated metastable compositions (y∼25%) near the indirect to direct band gap crossover predicted by first principles simulations. Extensive characterizations of composition, structure, and morphology show that the SiSnGeSn films grow lattice matched via a "compositional pinning" mechanism. The initial Raman observations of Si-Sn bond vibrations in a condensed phase are discussed in the context of simulated bond distributions in the alloys.