DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Impact of Electrical Contacts Design and Materials on the Stability of Ti Superconducting Transition Shape

Journal Article · · Journal of Low Temperature Physics
 [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [4];  [8];  [8];  [1];  [8];  [9];  [6];  [5];  [6];  [1];  [1];  [10] more »;  [7];  [11];  [12];  [1];  [9];  [6];  [11];  [13];  [6];  [7];  [5];  [6];  [6];  [3];  [6];  [14];  [1];  [15];  [12];  [14];  [1];  [3];  [16];  [7];  [7];  [7];  [1];  [9];  [15];  [17];  [14];  [9];  [1];  [7];  [7];  [1];  [1];  [4];  [12];  [8];  [11];  [6];  [7];  [18];  [7];  [5];  [19];  [20];  [16];  [7];  [3];  [2];  [5];  [17];  [15];  [1];  [21];  [3];  [17] « less
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Cardiff Univ., Cardiff (United Kingdom)
  3. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  5. National Inst. of Standards and Technology (NIST), Boulder, CO (United States)
  6. Univ. of California, Berkeley, CA (United States)
  7. Univ. of Chicago, Chicago, IL (United States)
  8. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  9. McGill Univ., Montreal, QC (Canada)
  10. McGill Univ., Montreal, QC (Canada); Canadian Institute for Advanced Research, Toronto (Canada)
  11. Univ. of Colorado, Boulder, CO (United States)
  12. Case Western Reserve Univ., Cleveland, OH (United States)
  13. Univ. of Illinois, Urbana, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
  14. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  15. Univ. of Illinois, Urbana, IL (United States)
  16. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  17. Univ. of Toronto, Toronto, ON (Canada)
  18. Three-Speed Logic, Inc.Vancouver (Canada)
  19. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  20. Stanford Univ., Stanford, CA (United States)
  21. Univ. of California, Los Angeles, CA (United States); Univ. of California, Berkeley, CA (United States)

The South Pole Telescope SPT-3G camera utilizes Ti/Au transition edge sensors (TESs). A key requirement for these sensors is reproducibility and long-term stability of the superconducting (SC) transitions. Here, we discuss the impact of electrical contacts design and materials on the shape of the SC transitions. Using scanning electron microscope, atomic force microscope, and optical differential interference contrast microscopy, we observed the presence of unexpected defects of morphological nature on the titanium surface and their evolution in time in proximity to Nb contacts. We found direct correlation between the variations of the morphology and the SC transition shape. Experiments with different diffusion barriers between TES and Nb leads were performed to clarify the origin of this problem. In conclusion, we have demonstrated that the reproducibility of superconducting transitions can be significantly improved by preventing diffusion processes in the TES-leads contact areas.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Organization:
National Science Foundation (NSF); Gordon and Betty Moore Foundation; USDOE Office of Science (SC), High Energy Physics (HEP); USDOE
Contributing Organization:
SPT
Grant/Contract Number:
AC02-06CH11357; AC02-76SF00515; PLR-1248097; PHY-1125897; AST-0956135; GBMF 947; AC02-07CH11359
OSTI ID:
1491023
Alternate ID(s):
OSTI ID: 1490471; OSTI ID: 1497093
Report Number(s):
FERMILAB-PUB-18-741-AE-PPD; 140107
Journal Information:
Journal of Low Temperature Physics, Vol. 193, Issue 5-6; ISSN 0022-2291
Publisher:
Plenum PressCopyright Statement
Country of Publication:
United States
Language:
English

References (13)

Large arrays of dual-polarized multichroic TES detectors for CMB measurements with the SPT-3G receiver conference July 2016
The effect of temperature and humidity on interdiffusion of gold and titanium in thin films journal April 1979
The role of hydrogen in altering the electrical properties of gold, titanium, and tungsten films journal April 1989
Fabrication-process-induced variations of Nb/Al/AlO x /Nb Josephson junctions in superconductor integrated circuits journal February 2010
Investigation of the Role of H in Fabrication-Process- Induced Variations of ${\rm Nb}/{\rm Al}/{\rm AlO}_{x}/{\rm Nb}$ Josephson Junctions journal June 2011
Room temperature gas-solid reaction of titanium on glass surfaces forming a very low resistivity layer journal September 2016
Microstructural characterizations of magnetron sputtered Ti films on glass substrate journal April 2009
Fabrication of Au/Ti TESs for Optical Photon Counting journal January 2008
Fabrication of large dual-polarized multichroic TES bolometer arrays for CMB measurements with the SPT-3G camera journal August 2015
Correlation of Critical Temperatures and Electrical Properties in Titanium Films journal March 2003
Optimization of Transition Edge Sensor Arrays for Cosmic Microwave Background Observations With the South Pole Telescope journal June 2017
Investigation of the titanium superconducting transition as a temperature reference point below 0.65 K journal June 2000
Effect of Dissolved Gases on Some Superconducting Properties of Niobium journal October 1963