High-$Q$ superconducting resonators fabricated in an industry-scale semiconductor-fabrication facility

TL;DR

This paper demonstrates the fabrication of high-$Q$ superconducting resonators using industry-scale semiconductor processes, achieving high quality factors suitable for quantum computing applications.

Contribution

It introduces a scalable manufacturing process for superconducting quantum circuits with high uniformity and quality, using standard semiconductor fabrication facilities.

Findings

Cryogenic Q-factors exceeding 10^6 in single-photon regime

Successful integration of Niobium air bridges without quality loss

High material and process quality in 200 mm production line

Abstract

Universal quantum computers promise to solve computational problems that are beyond the capabilities of known classical algorithms. To realize such quantum hardware on a superconducting material platform, a vast number of physical qubits has to be manufactured and integrated at high quality and uniformity on a chip. Anticipating the benefits of semiconductor industry processes in terms of process control, uniformity and repeatability, we set out to manufacture superconducting quantum circuits in a semiconductor fabrication facility. In order to set a baseline for the process quality, we report on the fabrication of coplanar waveguide resonators in a 200 mm production line, making use of a two-layer superconducting circuit technology. We demonstrate high material and process quality by cryogenic Q-factor measurements exceeding $10^6$ in the single-photon regime, for microwave resonators made of both Niobium and Tantalum. In addition, we demonstrate the incorporation of superconducting Niobium air bridges in our process, while maintaining the high quality factor of Niobium resonators.