Hydrogen plasma-assisted atomic layer epitaxy of superconducting titanium nitride
Abstract
Atomic layer deposition (ALD) offers precise, conformal control of thin-film growth and is a workhorse for semiconductor manufacturing, but its use in superconducting quantum circuits is constrained by the need to simultaneously control crystallinity, stoichiometry and interfacial disorder at cryogenic temperatures. Here we develop hydrogen plasma assisted ALD to epitaxially grow superconducting titanium nitride (TiN) thin films, using a hydrogen plasma step to modify the surface chemistry to suppress precursor-derived impurities during each deposition cycle. Synchrotron X-ray scattering reveals semi-coherent epitaxy of TiN on c-plane sapphire, with discrete crystallographic domains and minimal long-range structural disorder. Complementary X-ray spectroscopy and neutron reflectometry show negligible oxygen-related disorder throughout the film and no substantial hydrogen incorporation. The resulting TiN films exhibit a superconducting transition at 2.2 K, a kinetic inductance of 15 pH/sq and a superconducting coherence length of 14.6 nm, comparable to the measured crystal coherence length. These results establish hydrogen plasma assisted ALD as a route to structurally ordered superconducting TiN thin film epitaxy and demonstrate that the nanoscale control of ALD can be extended to materials suitable for cryogenic quantum technologies.
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BibTeX
@misc{chen2026hydrogen,
title = {{Hydrogen plasma-assisted atomic layer epitaxy of superconducting titanium nitride}},
author = {Yi-Hsun Chen and Yin-Chun Huang and Zachary Degnan and David Sommers and Kaijian Xing and Manjith Bose and Eduardo Solano and David Cortie and Michael Fuhrer and Julian A. Steele and Peter Jacobson and Miin-Jang Chen and Arkady Fedorov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.00956},
eprint = {2610.00956},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.00956},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Hydrogen plasma-assisted atomic layer epitaxy of superconducting titanium nitride
AU - Yi-Hsun Chen
AU - Yin-Chun Huang
AU - Zachary Degnan
AU - David Sommers
AU - Kaijian Xing
AU - Manjith Bose
AU - Eduardo Solano
AU - David Cortie
AU - Michael Fuhrer
AU - Julian A. Steele
AU - Peter Jacobson
AU - Miin-Jang Chen
AU - Arkady Fedorov
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.00956
UR - https://arxiv.org/abs/2610.00956
AB - Atomic layer deposition (ALD) offers precise, conformal control of thin-film growth and is a workhorse for semiconductor manufacturing, but its use in superconducting quantum circuits is constrained by the need to simultaneously control crystallinity, stoichiometry and interfacial disorder at cryogenic temperatures. Here we develop hydrogen plasma assisted ALD to epitaxially grow superconducting titanium nitride (TiN) thin films, using a hydrogen plasma step to modify the surface chemistry to suppress precursor-derived impurities during each deposition cycle. Synchrotron X-ray scattering reveals semi-coherent epitaxy of TiN on c-plane sapphire, with discrete crystallographic domains and minimal long-range structural disorder. Complementary X-ray spectroscopy and neutron reflectometry show negligible oxygen-related disorder throughout the film and no substantial hydrogen incorporation. The resulting TiN films exhibit a superconducting transition at 2.2 K, a kinetic inductance of 15 pH/sq and a superconducting coherence length of 14.6 nm, comparable to the measured crystal coherence length. These results establish hydrogen plasma assisted ALD as a route to structurally ordered superconducting TiN thin film epitaxy and demonstrate that the nanoscale control of ALD can be extended to materials suitable for cryogenic quantum technologies.
ER -