Nakamura, Y., Pashkin, Y. A. & Tsai, J. S. Coherent control of macroscopic quantum states in a single-Cooper-pair box. Nature 398, 786–788 (1999).

Article 
CAS 

Google Scholar
 

Koch, J. et al. Charge-insensitive qubit design derived from the Cooper pair box. Phys. Rev. A 76, 042319 (2007).

Siddiqi, I. Engineering high-coherence superconducting qubits. Nat. Rev. Mater. 6, 875–891 (2021).

Article 

Google Scholar
 

Google Quantum AI and Collaborators. Quantum error correction below the surface code threshold. Nature 638, 920–926 (2025).

Article 
CAS 

Google Scholar
 

Van Damme, J. et al. Advanced CMOS manufacturing of superconducting qubits on 300 mm wafers. Nature 634, 74–79 (2024).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Krinner, S. et al. Engineering cryogenic setups for 100-qubit scale superconducting circuit systems. EPJ Quantum Technol. 6, 2 (2019).

Martin, M. J. et al. Energy use in quantum data centers: scaling the impact of computer architecture, qubit performance, size, and thermal parameters. IEEE Trans. Sustain. Comput. 7, 864–874 (2022).

Article 

Google Scholar
 

Yang, C. H. et al. Operation of a silicon quantum processor unit cell above one kelvin. Nature 580, 350–354 (2020).

Article 
CAS 
PubMed 

Google Scholar
 

Anferov, A., Lee, K.-H., Zhao, F., Simon, J. & Schuster, D. I. Improved coherence in optically defined niobium trilayer-junction qubits. Phys. Rev. Appl. 21, 024047 (2024).

Anferov, A. et al. Superconducting qubits above 20 GHz operating over 200 mK. PRX Quantum 5, 020336 (2024).

Anferov, A., Wan, F., Harvey, S. P., Simon, J. & Schuster, D. I. Millimeter-wave superconducting qubit. PRX Quantum 6, 020336 (2025).

Article 

Google Scholar
 

Nakamura, Y. et al. Superconducting qubits consisting of epitaxially grown NbN/AlN/NbN Josephson junctions. Appl. Phys. Lett. 99, 212502 (2011).

Article 

Google Scholar
 

Kim, S. et al. Enhanced coherence of all-nitride superconducting qubits epitaxially grown on silicon substrate. Commun. Mater. 2, 21 (2021).

Tinkham, M. Introduction to Superconductivity 2nd edn (Dover Publications, 2004).

Wang, Z., Shinozaki, K., Murooka, Y., & Kuzmin, L. S. High-quality epitaxial NbN/AlN/NbN tunnel junctions with a wide range of current density. Appl. Phys. Lett. 102, 102601 (2013).

Makise, K., Terai, H. & Uzawa, Y. NbN/AlN/NbN/TiN tunnel junctions on Si (100) substrate for superconducting devices. IEEE Trans. Appl. Supercond. 26, 1100403 (2016).

Article 

Google Scholar
 

Qiu, W. & Terai, H. Fabrication of deep-sub-micrometer NbN/AlN/NbN epitaxial junctions on a Si-substrate. Appl. Phys. Express 13, 126501 (2020).

Article 
CAS 

Google Scholar
 

George, S. M. Atomic layer deposition: an overview. Chem. Rev. 110, 111–131 (2010).

Article 
CAS 
PubMed 

Google Scholar
 

Deyu, G. K. et al. Recent advances in atomic layer deposition of superconducting thin films: a review. Mater. Horiz. 12, 5594–5626 (2025).

Zhao, C. & Xiang, J. Atomic layer deposition (ALD) of metal gates for CMOS. Appl. Sci. 9, 2388 (2019).

Article 
CAS 

Google Scholar
 

Sheng, J. et al. Review article: atomic layer deposition for oxide semiconductor thin film transistors: advances in research and development. J. Vac. Sci. Technol. A 36, 060801 (2018).

Article 

Google Scholar
 

Waechtler, T. et al. ALD-grown seed layers for electrochemical copper deposition integrated with different diffusion barrier systems. Microelectron. Eng. 88, 684–689 (2011).

Article 
CAS 

Google Scholar
 

Chen, R. et al. Atomic layer deposition in advanced display technologies: from photoluminescence to encapsulation. Int. J. Extrem. Manuf. 6, 022003 (2024).

Article 

Google Scholar
 

Sowa, M. J. et al. Plasma-enhanced atomic layer deposition of superconducting niobium nitride. J. Vac. Sci. Technol. A 35, 01B143 (2017).

Article 

Google Scholar
 

Cheng, R., Wang, S. & Tang, H. X. Superconducting nanowire single-photon detectors fabricated from atomic-layer-deposited NbN. Appl. Phys. Lett. 115, 241101 (2019).

Article 

Google Scholar
 

Wilt, J. et al. Atomically thin Al2⁢O3 films for tunnel junctions. Phys. Rev. Appl. 7, 064022 (2017).

Jhabvala, C. A., Nagler, P. C. & Stevenson, T. R. Atomic layer deposition Josephson junctions for cryogenic circuit applications. J. Low. Temp. Phys. 200, 331–335 (2020).

Article 
CAS 

Google Scholar
 

Rosenberg, D. et al. 3D integrated superconducting qubits. npj Quantum Inf. 3, 42 (2017).

Alevli, M., Ozgit, C., Donmez, I. & Biyikli, N. The influence of N2/H2 and ammonia N source materials on optical and structural properties of AlN films grown by plasma enhanced atomic layer deposition. J. Cryst. Growth 335, 51–57 (2011).

Article 
CAS 

Google Scholar
 

Goerke, S. et al. Atomic layer deposition of AlN for thin membranes using trimethylaluminum and H2/N2 plasma. Appl. Surf. Sci. 338, 35–41 (2015).

Article 
CAS 

Google Scholar
 

Shibalov, M. V. et al. Ultrathin epitaxial NbNx film deposited by PEALD method on C-plane sapphire: growth, structure and superconducting properties. Appl. Surf. Sci. 612, 155697 (2023).

Article 
CAS 

Google Scholar
 

Dang, P. et al. An all-epitaxial nitride heterostructure with concurrent quantum hall effect and superconductivity. Sci. Adv. 7, eabf1388 (2021).

Article 
CAS 
PubMed 
PubMed Central 

Google Scholar
 

Yaddanapudi, K. First-principles study of structural phase transformation and dynamical stability of cubic AlN semiconductors. AIP Adv. 8, 125006 (2018).

Article 

Google Scholar
 

Chen, Z., Holec, D., Bartosik, M., Mayrhofer, P. H. & Zhang, Z. Crystallographic orientation dependent maximum layer thickness of cubic AlN in CrN/AlN multilayers. Acta Mater. 168, 190–202 (2019).

Article 
CAS 

Google Scholar
 

Shih, H.-Y. et al. Low-temperature atomic layer epitaxy of AlN ultrathin films by layer-by-layer, in-situ atomic layer annealing. Sci. Rep. 7, 17307 (2017).

Grönberg, L. et al. Side-wall spacer passivated sub-μm Josephson junction fabrication process. Supercond. Sci. Technol. 30, 125016 (2017).

Article 

Google Scholar
 

Higurashi, E., Okumura, K., Kunimune, Y., Suga, T. & Hagiwara, K. Room-temperature bonding of wafers with smooth Au thin films in ambient air using a surface-activated bonding method. IEICE Trans. Electron. E100.C, 156–160 (2017).

Article 

Google Scholar
 

Zhao, R. et al. Merged-element transmon. Phys. Rev. Appl. 14, 064006 (2020).

Article 
CAS 

Google Scholar
 

Mamin, H. J. et al. Merged-element transmons: design and qubit performance. Phys. Rev. Appl. 16, 034035 (2021).

Blais, A., Grimsmo, A. L., Girvin, S. M., & Wallraff, A. Circuit quantum electrodynamics. Rev. Mod. Phys. 93, 025005 (2021).

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).

Article 
CAS 
PubMed 
PubMed Central 

Google Scholar
 

Krantz, P. et al. A quantum engineer’s guide to superconducting qubits. Appl. Phys. Rev. 6, 021318 (2019).

Article 

Google Scholar
 

Gao, Y. Y., Rol, M. A., Touzard, S., & Wang, C. Practical guide for building superconducting quantum devices. PRX Quantum 2, 047001 (2021).

Paik, H. et al. Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture. Phys. Rev. Lett. 107, 240501 (2011).

Article 
PubMed 

Google Scholar
 

Catelani, G., Schoelkopf, R. J., Devoret, M. H. & Glazman, L. I. Relaxation and frequency shifts induced by quasiparticles in superconducting qubits. Phys. Rev. B 84, 064517 (2011).

Article 

Google Scholar
 

Serniak, K. et al. Hot nonequilibrium quasiparticles in transmon qubits. Phys. Rev. Lett. 121, 157701 (2018).

Jin, X. Y. et al. Thermal and residual excited-state population in a 3D transmon qubit. Phys. Rev. Lett. 114, 240501 (2015).

Article 
CAS 
PubMed 

Google Scholar
 

Lisenfeld, J., Lukashenko, A., Ansmann, M., Martinis, J. M. & Ustinov, A. V. Temperature dependence of coherent oscillations in Josephson phase qubits. Phys. Rev. Lett. 99, 170504 (2007).

Article 
CAS 
PubMed 

Google Scholar
 

Lvov, D. S., Lemziakov, S. A., Ankerhold, E., Peltonen, J. T. & Pekola, J. P. Thermometry based on a superconducting qubit. Phys. Rev. Appl. 23, 054079 (2025).

Article 
CAS 

Google Scholar
 

Ganjam, S. et al. Surpassing millisecond coherence in on chip superconducting quantum memories by optimizing materials and circuit design. Nat. Commun. 15, 3687 (2024).

Article 
CAS 
PubMed 
PubMed Central 

Google Scholar
 

Huang, S. et al. Microwave package design for superconducting quantum processors. PRX Quantum 2, 047003 (2021).

Tang, F. et al. Practical issues for atom probe tomography analysis of III-nitride semiconductor materials. Microsc. Microanal. 21, 544–556 (2015).

Article 
CAS 
PubMed 

Google Scholar