  For many years, Si1-yGey alloys have been applied in the semiconductor
industry due to the ability to adjust the performance of Si-based
nanoelectronic devices. Following this alloying approach of group-IV
semiconductors, adding tin (Sn) into the alloy appears as the obvious next
step, which leads to additional possibilities for tailoring the material
properties. Adding Sn enables effective band gap and strain engineering and can
improve the carrier mobilities, which makes Si1-x-yGeySnx alloys promising
candidates for future opto- and nanoelectronics applications. The bottom-up
approach for epitaxial growth of Si1-x-yGeySnx, e.g., by chemical vapor
deposition and molecular beam epitaxy, allows tuning the material properties in
the growth direction only; the realization of local material modifications to
generate lateral heterostructures with such a bottom-up approach is extremely
elaborate, since it would require the use of lithography, etching, and either
selective epitaxy or epitaxy and chemical-mechanical polishing giving rise to
interface issues, non-planar substrates, etc. This article shows the
possibility of fabricating Si1-x-yGeySnx alloys by Sn ion beam implantation
into Si1-yGey layers followed by millisecond-range flash lamp annealing (FLA).
The materials are investigated by Rutherford backscattering spectrometry, micro
Raman spectroscopy, X-ray diffraction, and transmission electron microscopy.
The fabrication approach was adapted to ultra-thin Si1-yGey layers on
silicon-on-insulator substrates. The results show the fabrication of
single-crystalline Si1-x-yGeySnx with up to 2.3 at.% incorporated Sn without
any indication of Sn segregation after recrystallization via FLA. Finally, we
exhibit the possibility of implanting Sn locally in ultra-thin Si1-yGey films
by masking unstructured regions on the chip.
