Akira Endo

Characterization of low-loss hydrogenated amorphous silicon films for superconducting resonators

  1. Bruno T. Buijtendorp,
  2. Juan Bueno,
  3. David J. Thoen,
  4. Vignesh Murugesan,
  5. Paolo M. Sberna,
  6. Jochem J.A. Baselmans,
  7. Sten Vollebregt,
  8. and Akira Endo
Superconducting resonators used in millimeter-submillimeter astronomy would greatly benefit from deposited dielectrics with a small dielectric loss. We deposited hydrogenated amorphous
silicon films using plasma-enhanced chemical vapor deposition, at substrate temperatures of 100°C, 250°C and 350° C. The measured void volume fraction, hydrogen content, microstructure parameter, and bond-angle disorder are negatively correlated with the substrate temperature. All three films have a loss tangent below 10−5 for a resonator energy of 105 photons, at 120 mK and 4-7 GHz. This makes these films promising for microwave kinetic inductance detectors and on-chip millimeter-submilimeter filters.
arxiv pdf