Characterization of superconducting through-silicon vias as capacitive elements in quantum circuits

TL;DR

This paper demonstrates the use of superconducting through-silicon vias as compact capacitive elements in quantum circuits, reducing size while maintaining quality for qubits and readout resonators.

Contribution

It introduces a novel application of superconducting TSVs as lumped element capacitors, enabling more compact quantum circuit components.

Findings

TSVs function effectively as capacitive elements in quantum circuits.

Significant reduction in circuit size compared to traditional approaches.

Measured devices show high-quality factors suitable for quantum applications.

Abstract

The large physical size of superconducting qubits and their associated on-chip control structures presents a practical challenge towards building a large-scale quantum computer. In particular, transmons require a high-quality-factor shunting capacitance that is typically achieved by using a large coplanar capacitor. Other components, such as superconducting microwave resonators used for qubit state readout, are typically constructed from coplanar waveguides which are millimeters in length. Here we use compact superconducting through-silicon vias to realize lumped element capacitors in both qubits and readout resonators to significantly reduce the on-chip footprint of both of these circuit elements. We measure two types of devices to show that TSVs are of sufficient quality to be used as capacitive circuit elements and provide a significant reductions in size over existing approaches.