Growth and Interface Engineering of Superconducting TiN on Sapphire by Thermal-Laser Epitaxy
Abstract
Thermal-laser epitaxy (TLE) extends the accessible pressure, temperature, and growth-rate regimes of conventional molecular-beam epitaxy, enabling in situ laser annealing, high-purity buffer-layer growth, and efficient evaporation of refractory elements. These capabilities make TLE a promising platform for engineering low-loss superconducting resonators and Josephson-junction heterostructures. Here, we study the TLE growth of TiN on sapphire and observe improved transport properties with increasing growth temperature up to 1150 C. Unfortunately, we observe that the high ammonia pressure and elevated substrate temperatures required for optimal TiN properties promote reactions at the sapphire surface, resulting in voids at the TiN-substrate interface. These defects increase interfacial surface area, introduce dangling bonds, and could compromise tunnel-barrier heterostructures. We mitigate this degradation using an initial TiN seed layer grown at 850 C. With the seed layer, we achieve a superconducting transition temperature of 5.8 K, a residual resistivity ratio of 12.2, and a resistivity of 1.19 micro-ohm cm at 10 K, which, to our knowledge, is the lowest reported for TiN grown on sapphire.
Related
- Highly crystalline superconducting TiN resonators grown on thermally reconstructed sapphire
- Hydrogen plasma-assisted atomic layer epitaxy of superconducting titanium nitride
- Encapsulation epitaxy of air-stable monolayer superconducting films for quantum circuits and qubits
- Enhanced thermal conductivity of (010) (AlxGa1-x)2O3 epitaxial films utilizing indium-catalyzed molecular beam epitaxy
- Correlation enhanced magnetism at a superconducting cuprate/manganite interface
BibTeX
@misc{hyatt2026growth,
title = {{Growth and Interface Engineering of Superconducting TiN on Sapphire by Thermal-Laser Epitaxy}},
author = {Anthony Hyatt and Anand Ithepalli and Eegene Clara Chung and Yorick A. Birkholzer and Brendan Faeth and Huili Grace Xing and David A. Muller and Darrell G. Schlom and Debdeep Jena},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.31721},
eprint = {2609.31721},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.31721},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Growth and Interface Engineering of Superconducting TiN on Sapphire by Thermal-Laser Epitaxy
AU - Anthony Hyatt
AU - Anand Ithepalli
AU - Eegene Clara Chung
AU - Yorick A. Birkholzer
AU - Brendan Faeth
AU - Huili Grace Xing
AU - David A. Muller
AU - Darrell G. Schlom
AU - Debdeep Jena
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.31721
UR - https://arxiv.org/abs/2609.31721
AB - Thermal-laser epitaxy (TLE) extends the accessible pressure, temperature, and growth-rate regimes of conventional molecular-beam epitaxy, enabling in situ laser annealing, high-purity buffer-layer growth, and efficient evaporation of refractory elements. These capabilities make TLE a promising platform for engineering low-loss superconducting resonators and Josephson-junction heterostructures. Here, we study the TLE growth of TiN on sapphire and observe improved transport properties with increasing growth temperature up to 1150 C. Unfortunately, we observe that the high ammonia pressure and elevated substrate temperatures required for optimal TiN properties promote reactions at the sapphire surface, resulting in voids at the TiN-substrate interface. These defects increase interfacial surface area, introduce dangling bonds, and could compromise tunnel-barrier heterostructures. We mitigate this degradation using an initial TiN seed layer grown at 850 C. With the seed layer, we achieve a superconducting transition temperature of 5.8 K, a residual resistivity ratio of 12.2, and a resistivity of 1.19 micro-ohm cm at 10 K, which, to our knowledge, is the lowest reported for TiN grown on sapphire.
ER -