Awschalom, D. D., Bernien, H., Hanson, R., Oliver, W. D. & Vučković, J. Challenges and opportunities for quantum information hardware. Science 390, 1004–1010 (2025).
de Leon, N. P. et al. Materials challenges and opportunities for quantum computing hardware. Science 372, eabb2823 (2021).
McRae, C. R. H. Measurement techniques for superconducting microwave resonators towards quantum device applications. In 2022 IEEE/MTT-S International Microwave Symposium (IMS) 230–232 (IEEE, 2022).
Place, A. P. M. et al. New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds. Nat. Commun. 12, 1779 (2021).
Crowley, K. D. et al. Disentangling losses in tantalum superconducting circuits. Phys. Rev. X 13, 041005 (2023).
Lozano, D. P. et al. Low-loss α-tantalum coplanar waveguide resonators on silicon wafers: fabrication, characterization and surface modification. Mater. Quantum Technol. 4, 025801 (2024).
Ganjam, S. et al. Surpassing millisecond coherence in on-chip superconducting quantum memories by optimizing materials and circuit design. Nat. Commun. 15, 3687 (2024).
Marcaud, G. et al. Low-loss superconducting resonators fabricated from tantalum films grown at room temperature. Commun. Mater. 6, 182 (2025).
Bland, M. P. et al. Millisecond lifetimes and coherence times in 2D transmon qubits. Nature 647, 343–348 (2025).
McRae, C. R. H. et al. Reproducible coherence characterization of superconducting quantum devices. Appl. Phys. Lett. 119, 100501 (2021).
Torres-Castanedo, C. G. et al. Formation and microwave losses of hydrides in superconducting niobium thin films resulting from fluoride chemical processing. Adv. Funct. Mater. 34, 2401365 (2024).
Kono, S. et al. Mechanically induced correlated errors on superconducting qubits with relaxation times exceeding 0.4 ms. Nat. Commun. 15, 3950 (2024).
Olszewski, M. W. et al. Low-loss Nb on Si superconducting resonators from a dual-use spintronics deposition chamber and with acid-free post-processing. Appl. Phys. Lett. 128, 214001 (2026).
Gingras, M. A. et al. Improving transmon qubit performance with fluorine-based surface treatments. Phys. Rev. Applied 26, 014040 (2026).
Zikiy, E. V. et al. Investigation of tantalum films growth for coplanar resonators with internal quality factors above ten million. Appl. Phys. Rev. 13, 021418 (2026).
Tong, X. C. Advanced Materials for Integrated Optical Waveguides Springer Series in Advanced Microelectronics Vol. 46 (Springer, 2014).
Wang, C. et al. Surface participation and dielectric loss in superconducting qubits. Appl. Phys. Lett. 107, 162601 (2015).
Calusine, G. et al. Analysis and mitigation of interface losses in trenched superconducting coplanar waveguide resonators. Appl. Phys. Lett. 112, 062601 (2018).
Kopas, C. J. et al. Simple coplanar waveguide resonator mask targeting metal-substrate interface. Preprint at https://arxiv.org/abs/2204.07202 (2022).
Khalil, M. S., Stoutimore, M. J. A., Wellstood, F. C. & Osborn, K. D. An analysis method for asymmetric resonator transmission applied to superconducting devices. J. Appl. Phys. 111, 054510 (2012).
McRae, C. R. H. et al. Materials loss measurements using superconducting microwave resonators. Rev. Sci. Instrum. 91, 091101 (2020).
Turiansky, M. E. & Van de Walle, C. G. Dielectric loss due to charged-defect acoustic phonon emission. APL Quantum 1, 026114 (2024).
Zhou, H. et al. Observation of interface piezoelectricity in superconducting devices on silicon. Nat. Commun. 17, 377 (2026).
Rieger, D. et al. Fano interference in microwave resonator measurements. Phys. Rev. Appl. 20, 014059 (2023).
Altoé, M. V. P. et al. Localization and mitigation of loss in niobium superconducting circuits. PRX Quantum 3, 020312 (2022).
Verjauw, J. et al. Investigation of microwave loss induced by oxide regrowth in high-Q niobium resonators. Phys. Rev. Appl. 16, 014018 (2021).
Lozano, D. P. et al. Reversing hydrogen-related loss in α-Ta thin films for quantum device fabrication. Adv. Sci. 12, e09244 (2025).
Tuokkola, M. et al. Methods to achieve near-millisecond energy relaxation and dephasing times for a superconducting transmon qubit. Nat. Commun. 16, 5421 (2025).
Kriekebaum, J. Superconducting Qubit Enabled Single Microwave Photon Detection. PhD thesis, Univ. California, Berkeley (2020).
Van Damme, J. et al. Argon-milling-induced decoherence mechanisms in superconducting quantum circuits. Phys. Rev. Appl. 20, 014034 (2023).
Grünhaupt, L. et al. An argon ion beam milling process for native AlOx layers enabling coherent superconducting contacts. Appl. Phys. Lett. 111, 072601 (2017).
Manzo-Perez, M. et al. Physical patterning of high-Q superconducting niobium resonators via ion beam etching. Appl. Phys. Lett. 127, 092601 (2025).
Zhang, Z.-H. et al. Acceptor-induced bulk dielectric loss in superconducting circuits on silicon. Phys. Rev. X 14, 041022 (2024).
Benvenuti, C. et al. Study of the surface resistance of superconducting niobium films at 1.5 GHz. Physica C 316, 153–188 (1999).
Matson, D. W., McClanahan, E. D., Rice, J. P., Lee, S. L. & Windover, D. Effect of sputtering parameters on Ta coatings for gun bore applications. Surf. Coat. Technol. 133/134, 411–416 (2000).
Lee, S. L., Windover, D., Audino, M., Matson, D. W. & McClanahan, E. D. High-rate sputter deposited tantalum coating on steel for wear and erosion mitigation. Surf. Coat. Technol. 149, 62–69 (2002).
Petrov, I., Ivanov, I., Orlinov, V. & Sundgren, J. Comparison of magnetron sputter deposition conditions in neon, argon, krypton, and xenon discharges. J. Vac. Sci. Technol. A 11, 2733–2741 (1993).
Paturaud, C., Farges, G., Sainte Catherine, M. C. & Machet, J. Influence of sputtering gases on the properties of magnetron sputtered tungsten films. Surf. Coat. Technol. 86/87, 388–393 (1996).
Ganjam, S. Improving the Coherence of Superconducting Quantum Circuits through Loss Characterization and Design Optimization. PhD thesis, Yale Univ. (2023).
Choi, J. et al. Low barrier ZrOx-based Josephson junctions. APL Mater. 13, 111103 (2025).
Yang, C. et al. Superconducting gap engineering in tantalum-alloy-based resonators. Proc. Natl. Acad. Sci. USA 123, e2519940123 (2026).
Bahrami, F. et al. Vortex motion induced losses in tantalum resonators. Phys. Rev. B 113, 054505 (2026).
Feinstein, L. G. & Huttemann, R. D. Factors controlling the structure of sputtered Ta films. Thin Solid Films 16, 129–145 (1973).
Sato, S. Nucleation properties of magnetron-sputtered tantalum. Thin Solid Films 94, 321–329 (1982).
Urade, Y. et al. Microwave characterization of tantalum superconducting resonators on silicon substrate with niobium buffer layer. APL Mater. 12, 021132 (2024).
Anferov, A., Lee, K.-H., Zhao, F., Simon, J. & Schuster, D. I. Improved coherence in optically-defined niobium trilayer junction qubits. Phys. Rev. Applied 21, 024047 (2024).
Sethi, P. et al. Native-oxide-passivated trilayer junctions for superconducting qubits. Phys. Rev. Applied 24, 064056 (2025).
Bhatia, E. et al. Ta-based Josephson junctions using insulating ALD TaN tunnel barriers. Preprint at https://arxiv.org/abs/2511.20266 (2025).
Potluri, R. et al. Fabrication and structural analysis of trilayers for tantalum Josephson junctions with Ta2O5 barriers. Preprint at https://arxiv.org/abs/2510.20114 (2025).
Baity, P. G. et al. Circle fit optimization for resonator quality factor measurements: point redistribution for maximal accuracy. Phys. Rev. Res. 6, 013329 (2024).
Boulder Cryogenic Quantum Testbed scresonators: data analysis code for cryogenic resonator measurement. GitHub https://github.com/Boulder-Cryogenic-Quantum-Testbed/scresonators (2025).
Stefanazzi, L. et al. The QICK (Quantum Instrumentation Control Kit): readout and control for qubits and detectors. Rev. Sci. Instrum. 93, 044709 (2022).
Ding, C. et al. Experimental advances with the QICK (Quantum Instrumentation Control Kit) for superconducting quantum hardware. Phys. Rev. Res. 6, 013305 (2024).
Olszewski, M. W. Krypton-sputtered tantalum films for scalable high-performance quantum devices. Zenodo https://doi.org/10.5281/zenodo.17650482 (2025).