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

Understand

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.