Enhanced Secondary-Electron Detection of Single-Ion Implants in Silicon through Thin SiO<sub>2</sub> Layers.

Schneider, E B; Lloyd-Willard, O G; Stockbridge, K; Ludlow, M; Eserin, S; Antwis, L; Cox, D C; Webb, R P et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Deterministic placement of single dopants is essential for scalable quantum devices based on Group V donors in silicon. We demonstrate a nondestructive, high-efficiency method for detecting individual ion implantation events using secondary electrons (SEs) in a focused-ion-beam system. Using low-energy Sb ions implanted into undoped silicon, we achieve up to 98 ± 1% single-ion detection efficiency (DE). We find that introducing thin, controlled SiO<sub>2</sub> capping layers enhances the SE yield, consistent with the increased electron mean-free path in the oxide, while maintaining successful ion deposition in the underlying silicon substrate. Our approach provides a robust and scalable route to precise donor placement and extends deterministic implantation strategies to a broad range of material systems and quantum device architectures.