In this work we present a new fabrication process that enabled the fabrication of superconducting nanowire single photon detectors SNSPD with fill-factors as high as 88% with gaps between nanowires as small as 12 nm. This fabrication process combined high-resolution electron-beam lithography with photolithography. Although this work was motivated by the potential of increased detection efficiency with higher fill-factor devices, test results showed an unexpected systematic suppression in device critical currents with increasing fill-factor.
Bibliographical noteFunding Information:
Manuscript received January 13, 2009. First published June 30, 2009; current version published July 10, 2009. This work was sponsored by the US Air Force under Air Force Contract FA8721-05-C-0002 and by the Intelligence Advanced Research Projects Activity (IARPA). J. K. W. Yang was supported by the Agency for Science, Technology and Research (A*STAR) Singapore. J. K. W. Yang, B. Cord and K. K. Berggren are with the Massachusetts Institute of Technology, Cambridge, MA 02139 USA (e-mail: firstname.lastname@example.org). A. J. Kerman, E. A. Dauler and R. J. Molnar are with the Massachusetts Institute of Technology Lincoln Laboratory, Lexington, MA 02420, USA. V. Anant is with Exponent, Inc., Natick, MA 01760, USA. He was with the Massachusetts Institute of Technology, Cambridge, MA 02139 USA. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TASC.2009.2017953
- Critical current
- Detection efficiency
- Single-photon detectors