A superinductor in a deep sub-micron integrated circuit

TL;DR

This paper demonstrates a silicon-integrated superinductor using TiN thin films with high kinetic inductance, enabling advanced quantum sensors and potentially impacting quantum computing, sensing, and metamaterials.

Contribution

It introduces a superinductor fabricated within a silicon IC using TiN, combining high impedance with integration benefits for quantum sensing and other applications.

Findings

Achieved a superinductor with impedance exceeding $R_Q$ within a silicon IC.

Enhanced rfSET sensitivity by over two orders of magnitude.

Reduced device area by a factor of 10,000.

Abstract

Superinductors are circuit elements characterised by an intrinsic impedance in excess of the superconducting resistance quantum ($R_\text{Q}\approx6.45~$k$\Omega$), with applications from metrology and sensing to quantum computing. However, they are typically obtained using exotic materials with high density inductance such as Josephson junctions, superconducting nanowires or twisted two-dimensional materials. Here, we present a superinductor realised within a silicon integrated circuit (IC), exploiting the high kinetic inductance ($\sim 1$~nH/$\square$) of TiN thin films native to the manufacturing process (22-nm FDSOI). By interfacing the superinductor to a silicon quantum dot formed within the same IC, we demonstrate a radio-frequency single-electron transistor (rfSET), the most widely used sensor in semiconductor-based quantum computers. The integrated nature of the rfSET reduces its parasitics which, together with the high impedance, yields a sensitivity improvement of more than two orders of magnitude over the state-of-the-art, combined with a 10,000-fold area reduction. Beyond providing the basis for dense arrays of integrated and high-performance qubit sensors, the realization of high-kinetic-inductance superconducting devices integrated within modern silicon ICs opens many opportunities, including kinetic-inductance detector arrays for astronomy and the study of metamaterials and quantum simulators based on 1D and 2D resonator arrays.