Epitaxial SiGeSn grown on Si by ion implantation

We have formed Si_xGe_1−x−ySn_y compounds on Si substrates by ion implantation and annealing and investigated their concentration profiles, crystallization, and optical properties. Ge and Sn ions were implanted in the range (2.5–10) × 10¹⁶ Ge/cm² at 65 keV, and (1.0–4.0) × 10¹⁶ Sn/cm² at 100 keV, resulting in a peak implant dose at a depth of 50 nm for both species. Epitaxially regrown Si_xGe_1−x−ySn_y layers (110 nm thick) were produced with Ge and Sn contents that allowed bandgap tuning in the (0.88–1.1) eV range. Shifts in photoelectron binding energies (Si 2p, Ge 3d, and Sn 3d) were consistent with ternary compound formation. Sn segregation was observed for annealing temperatures ≥600 °C. A significant increase in the optical absorption coefficient (×10⁴ cm⁻¹ for λ = (800–1700) nm) was observed for SiGe, SiSn, and SiGeSn alloys, with SiGeSn having coefficients several orders of magnitude higher than for Si. Contributions of segregated Sn to these properties were observed. Metastable Si_xGe_1−x−ySn_y layers were achieved, which may point to a promising route to mitigate Sn incorporation challenges for near-infrared detectors.