PT Unknown
AU Finkel, M
   Vachtomin, Y
   Antipov, S
   Drakinski, V
   Kaurova, N
   Voronov, B
   Goltsman, G
TI Gain bandwidth and noise temperature of NbTiN HEB mixer
SE Proc. 14[super:th] Int. Symp. Space Terahertz Technol.
PY 2003
BP 276
EP 285
DE NbTiN HEB mixer
AB We have determined that the gain bandwidth of phonon-cooled HEB mixer employing NbTiN films deposited on MgO layer over Si substrate is limited b y the escape of phonons to the substrate. The cut-off frequencies of 1 um long devices operating at T 71, based on 3.5 nm. 4 nm and 10 nm thick _films amount to 400 Mk. 300 MHz, and 100 MHz, respectivel y . The gain bandwidth of 0.13 . um long devices fabricated from 3.5 nm thick _film is larger and amounts to 0.8 GIL; at the optimal operating point and to 1.5 GIL: at larger bias. The increase of the gain bandwidth from 400 MHz up to 1.5 GH: with the change of bridge length is attributed to diffusion cooling. A double sideband noise temperature of 4000 K was obtained _for heterodyne receiver utilizing pilot NbTiN HEB mixer (not optimized for normal state resistance) operating at the local oscillator _frequency of 2.5 THz.
ER