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arXiv · 2509.14133

Room temperature reactive sputtering deposition of titanium nitride with high sheet kinetic inductance

Juliang Li·Peter S. Barry·Tom Cecil·Marharyta Lisovenko·Volodymyr Yefremenko·Gensheng Wang·Serhii Kruhlov·Goran Karapetrov·Clarence Chang
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Abstract

Superconducting thin films with high intrinsic kinetic inductance $L_{k}$ are important for high-sensitivity detectors, enabling strong coupling in hybrid quantum systems, and enhancing nonlinearities in quantum devices. We report the room-temperature reactive sputtering of titanium nitride thin films with a critical temperature $T_{c}$ of \SI{3.8}{K} and a thickness of \SI{27}{nm}. Fabricated into resonators, these films exhibit a sheet kinetic inductance $L_{k, \square}$ of 394~$\textrm{pH}/\square$, as inferred from resonant frequency measurements. %from this film and measure quality factors of $4\times 10^{4}$; these quality factors are likely limited by the low resistivity wafer. X-ray diffraction analysis confirms the formation of stoichiometric TiN, with no residual unreacted titanium. The films also demonstrate a characteristic sheet resistivity of 475~$Ω/\square$, yielding an impedance an order of magnitude higher than conventional 50~$Ω$ resonators. This property could enhance microwave single\textendash photon coupling strength by an order of magnitude, offering transformative potential for hybrid quantum systems and quantum sensing. Furthermore, the high $L_{k}$ enables Kerr nonlinearities comparable to state\textendash of\textendash the\textendash art quantum devices. Combined with its relatively high $T_{c}$, this thin film presents a promising platform for superconducting devices, including amplifiers and qubits operating at higher temperatures.

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Juliang Li, Peter S. Barry, Tom Cecil, Marharyta Lisovenko, Volodymyr Yefremenko, Gensheng Wang, Serhii Kruhlov, Goran Karapetrov, Clarence Chang. 2025-09-17. Room temperature reactive sputtering deposition of titanium nitride with high sheet kinetic inductance. https://arxiv.org/abs/2509.14133

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