Si1-x-yGeySnx alloy formation by Sn ion implantation and flash lamp annealing

TL;DR

This paper demonstrates a novel method for fabricating single-crystalline Si1-x-yGeySnx alloys with up to 2.3 at.% Sn using Sn ion implantation and flash lamp annealing, enabling local alloy modifications for nanoelectronic applications.

Contribution

It introduces a new fabrication approach combining Sn ion implantation and flash lamp annealing to create Si1-x-yGeySnx alloys with controlled Sn incorporation and local patterning capabilities.

Findings

Achieved single-crystalline Si1-x-yGeySnx with up to 2.3 at.% Sn

No Sn segregation observed after flash lamp annealing

Enabled local Sn implantation through masking techniques

Abstract

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.