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

Bruno T. Buijtendorp*, Juan Bueno, David J. Thoen, Vignesh Murugesan, Paolo M. Sberna, Jochem J.A. Baselmans, Sten Vollebregt, Akira Endo

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Superconducting circuit elements used in millimeter-submillimeter (mm-submm) astronomy would greatly benefit from deposited dielectrics with small dielectric loss and noise. This will enable the use of multilayer circuit elements and thereby increase the efficiency of mm-submm filters and allow for a miniaturization of microwave kinetic inductance detectors (MKIDs). Amorphous dielectrics introduce excess loss and noise compared with their crystalline counterparts, due to two-level system defects of unknown microscopic origin. 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 to 7 GHz. This makes these films promising for MKIDs and on-chip mm-submm filters.

Original languageEnglish
Article number028006
Number of pages13
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Volume8
Issue number2
DOIs
Publication statusPublished - 2022

Keywords

  • amorphous silicon
  • dielectric loss
  • filter bank
  • kinetic inductance detectors
  • millimeter-submillimeter
  • spectrometer

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