Isotopic enrichment of silicon: A molecular dynamics study on ²⁸Si ion implantation at low energies.

Abstract

High-fluence silicon-28 (²⁸Si) ion implantation has been shown to produce isotopically enriched surface regions within natural silicon (Si) wafers through localized focused ion beam implantation. In this work, molecular dynamics simulations are performed to simulate ²⁸Si ion implantations into a Si sample for insights into the enrichment process dynamics. We conduct a series of simulations to emulate the irradiation process at incident energies, ranging from 0.5 to 2 keV, and fixed angles of incidence of 0°, 7°, and 15°. Our findings elucidate how implantation energy and angle of incidence affect sputter yield and enrichment levels. The outcomes of this study highlight the importance of atomistic simulations in providing a mechanistic understanding of deposition and sputtering for the optimization of the enrichment process. Moreover, comparisons with transmission electron microscopy images of natural silicon wafers enriched using focused ion beam performed by Acharya et al. [Commun. Mater. 5, 57 (2024)], show strong agreement for both postirradiated and postannealed configurations, further validating the simulation approach. This work will support future studies of isotopic enrichment of natural Si and the development of novel methods to fabricate spin-qubit devices for quantum computing architectures.

• BibTex.
• DOI: https://doi.org/10.1103/6l4s-tgsw.