PT Unknown
AU Yagubov, P
   Gol'tsman, G
   Voronov, B
   Seidman, L
   Siomash, V
   Cherednichenko, S
   Gershenzon, E
TI The bandwidth of HEB mixers employing ultrathin NbN films on sapphire substrate
SE Proc. 7[super:th] Int. Symp. Space Terahertz Technol.
PY 1996
BP 290
EP 302
DE NbN HEB mixers; fabrication process
AB We report on some unusual features observed during fabrication of ultrathin NbN films with high Tc. The films were used to fabricate HEB mixers, which were evaluated for IF bandwidth measurements at 140 GHz. Ultrathin films were fabricated using reactive dc magnetron sputtering with a discharge current source. Reproducible parameters of the films are assured keeping constant the difference between the discharge voltage in pure argon, and in a gas mixture, for the same current. A maximum bandwidth of 4 GHz at optimal LO and dc bias was obtained for mixer chip based on NbN film 35 A thick with Tc = 11 K.
PI Charlottesville, Virginia, USA
ER