Amorphization-Depth-Dependent Bismuth Redistribution and Activation in Silicon for Quantum Devices
Abstract
Near-surface bismuth donors are promising for silicon quantum devices because of their rich electron-nuclear spin structure and long spin coherence, but their electrical activation is strongly influenced by implantation-induced amorphization. We compare redistribution and electrical activation of 20 keV Bi implanted directly into Si and after Si preamorphization. The two routes produce amorphous-layer depths of approximately 47 nm and 177 +/- 15 nm, respectively. After annealing at 650 C for 300 s, Rutherford backscattering spectrometry and channeling reveal comparable substitutional Bi fractions of 91 +/- 2% and 89 +/- 4%, whereas Hall measurements indicate Hall-derived electrical activation yields of approximately 60% and 90%, respectively. Depth-resolved ion-scattering analysis reveals a buried Bi-related feature at or beyond the initial amorphous/crystalline interface, within the end-of-range region, together with increasing surface segregation at higher annealing temperatures. The buried feature is consistent with trapping near residual end-of-range defects. X-ray photoelectron spectroscopy and low-temperature photoluminescence on the Bi-only sample reveal no resolvable Bi-oxide contribution and a donor-related optical signature, respectively. These results show that amorphization depth and regrowth geometry govern Bi redistribution and influence electrical activation beyond substitutional incorporation alone.
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BibTeX
@misc{bioud2026amorphizationdepthdependent,
title = {{Amorphization-Depth-Dependent Bismuth Redistribution and Activation in Silicon for Quantum Devices}},
author = {Youcef A. Bioud and Simon-Jean Michel and Sebastien Francoeur and Sjoerd Roorda and Eva Dupont-Ferrier},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35993},
eprint = {2610.35993},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35993},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Amorphization-Depth-Dependent Bismuth Redistribution and Activation in Silicon for Quantum Devices
AU - Youcef A. Bioud
AU - Simon-Jean Michel
AU - Sebastien Francoeur
AU - Sjoerd Roorda
AU - Eva Dupont-Ferrier
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.35993
UR - https://arxiv.org/abs/2610.35993
AB - Near-surface bismuth donors are promising for silicon quantum devices because of their rich electron-nuclear spin structure and long spin coherence, but their electrical activation is strongly influenced by implantation-induced amorphization. We compare redistribution and electrical activation of 20 keV Bi implanted directly into Si and after Si preamorphization. The two routes produce amorphous-layer depths of approximately 47 nm and 177 +/- 15 nm, respectively. After annealing at 650 C for 300 s, Rutherford backscattering spectrometry and channeling reveal comparable substitutional Bi fractions of 91 +/- 2% and 89 +/- 4%, whereas Hall measurements indicate Hall-derived electrical activation yields of approximately 60% and 90%, respectively. Depth-resolved ion-scattering analysis reveals a buried Bi-related feature at or beyond the initial amorphous/crystalline interface, within the end-of-range region, together with increasing surface segregation at higher annealing temperatures. The buried feature is consistent with trapping near residual end-of-range defects. X-ray photoelectron spectroscopy and low-temperature photoluminescence on the Bi-only sample reveal no resolvable Bi-oxide contribution and a donor-related optical signature, respectively. These results show that amorphization depth and regrowth geometry govern Bi redistribution and influence electrical activation beyond substitutional incorporation alone.
ER -