Corey Rae H McRae

Low-loss Nb on Si superconducting resonators from a dual-use spintronics deposition chamber and with acid-free post-processing

  1. Maciej W. Olszewski,
  2. Jadrien T. Paustian,
  3. Tathagata Banerjee,
  4. Haoran Lu,
  5. Jorge L. Ramirez,
  6. Nhi Nguyen,
  7. Kiichi Okubo,
  8. Rohit Pant,
  9. Aleksandra B. Biedron,
  10. Daniel C. Ralph,
  11. Christopher J. K. Richardson,
  12. Gregory D. Fuchs,
  13. Corey Rae H McRae,
  14. Ivan V. Pechenezhskiy,
  15. B. L. T. Plourde,
  16. and Valla Fatemi
Magnetic impurities are known to degrade superconductivity. For this reason, physical vapor deposition chambers that have previously been used for magnetic materials have generally
been avoided for making high-quality superconducting resonator devices. In this article, we show by example that such chambers can be used: with Nb films sputtered in a chamber that continues to be used for magnetic materials, we demonstrate compact (3 {\mu}m gap) coplanar waveguide resonators with low-power internal quality factors near one million. We achieve this using a resist strip bath with no post-fabrication acid treatment, which results in performance comparable to previous strip baths with acid treatments. We also find evidence that this improved resist strip bath provides a better surface chemical template for post-fabrication hydrogen fluoride processing. These results are consistent across three Si substrate preparation methods, including a \SI{700}{\celsius} anneal.
arxiv pdf

Simple coplanar waveguide resonator mask targeting metal-substrate interface

  1. Cameron J. Kopas,
  2. Ella Lachman,
  3. Corey Rae H McRae,
  4. Yuvraj Mohan,
  5. Josh Y. Mutus,
  6. Ani Nersisyan,
  7. and Amrit Poudel
This white paper presents a single-layer mask, found at this https URL. It is designed for fabrication of superconducting microwave resonators towards 1:1 comparisons of dielectric
losses from the metal-substrate interface. Finite-element electromagnetic simulations are used to determine participation ratios of the four major regions of the on-chip devices, as well as to confirm lack of crosstalk between neighboring devices and demonstrate coupling tunability over three orders of magnitude. This mask is intended as an open-source community resource for facilitating precise and accurate comparisons of materials in the single-photon, millikelvin regime.
arxiv pdf

Perspective: Reproducible Coherence Characterization of Superconducting Quantum Devices

  1. Corey Rae H McRae,
  2. Gregory M Stiehl,
  3. Haozhi Wang,
  4. Sheng-Xiang Lin,
  5. Shane A. Caldwell,
  6. David P. Pappas,
  7. Josh Mutus,
  8. and Joshua Combes
As the field of superconducting quantum computing approaches maturity, optimization of single-device performance is proving to be a promising avenue towards large-scale quantum computers.
However, this optimization is possible only if performance metrics can be accurately compared among measurements, devices, and laboratories. Currently such comparisons are inaccurate or impossible due to understudied errors from a plethora of sources. In this Perspective, we outline the current state of error analysis for qubits and resonators in superconducting quantum circuits, and discuss what future investigations are required before superconducting quantum device optimization can be realized.
arxiv pdf