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Title: Tuning the transition temperature of WSi$$_{x}$$ alloys for use in cryogenic microcalorimeters

Here, microwave kinetic inductance detectors (MKID) provide a pathway to highly multiplexed, high-resolution, detectors. Over the past several years we have introduced the concept of the Thermal Kinetic Inductance Detector (TKID), which operates as a microcalorimeter. As with other microcalorimeters, the thermal noise of a TKID is reduced when the operating temperature is decreased. However, because the sensitivity of a TKID decreases as the operating temperature drops below 20% of T C, the T C of the resonator material must be tuned to match the desired operating temperature. We have investigated the WSi$$_{x}$$ alloy system as a material for these detectors. By co-sputtering from a Si andW2Si target, we have deposited WSi$$_{x}$$ films with a tunable T C that ranges from 5 K down to 500 mK. These films provide a large kinetic inductance fraction and relatively low noise levels. We provide results of these studies showing the T C, resistivity, quality factors, and noise as a function of deposition conditions. These results show that WSi$$_{x}$$ is a good candidate for TKIDs.
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States); Northwestern Univ., Evanston, IL (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Low Temperature Physics
Additional Journal Information:
Journal Volume: 184; Journal Issue: 1-2; Journal ID: ISSN 0022-2291
Plenum Press
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; low temperature detector; kinetic inductance detector; materials; tungsten silicide
OSTI Identifier: