Noise and Bandwidth of 0.5-THz Twin Vertically Stacked SIS Junctions

Author

Li, Jing ; Shi, Sheng-Cai ; Liu, Dong ; Zhou, Kang-Ming ; Wang, MingJye ; Chen, Tse-Jun ; Chen, Chong-Wen ; Lu, Wei-Chun ; Chiu, ChuangPing ; Chang, Hsian-Hong

Author_Institution

Purple Mountain Obs., Chinese Acad. of Sci., Nanjing, China

Volume

21

Issue

3

fYear

2011

fDate

6/1/2011 12:00:00 AM

Firstpage

663

Lastpage

666

Abstract

Twin SIS (superconductor-insulator-superconductor) junctions, with a simple structure, yet large bandwidth and low noise temperature, have been widely used in millimeter- and submillimeter-wave heterodyne mixers. With increasing frequency, however, the length of the tuning inductance connecting the two individual SIS junctions becomes short while the junction area remains fixed. With a relatively short tuning inductance, the effect of the junction´s spreading inductance becomes non-negligible, and device fabrication becomes more difficult. By adopting vertically stacked SIS junctions (VSJs), which have an equivalent geometric capacitance inversely proportional to the junction number, it becomes feasible to increase the junction tuning inductance. In this paper, we report on the design, fabrication, and characterization of twin Nb/Al-AlOx/Nb/Al-AlOx/Nb VSJs for the 500-GHz frequency band.

Keywords

aluminium compounds; niobium; submillimetre wave mixers; superconductor-insulator-superconductor mixers; Nb-Al-AlO_x-Nb-Al-AlO_x-Nb; VSJ; frequency 0.5 THz; stacked SIS junctions; submillimeter-wave heterodyne mixers; superconductor-insulator-superconductor junction; vertically stacked SIS junctions; Impedance; Inductance; Junctions; Mixers; Niobium; Noise; Tuning; Mixer noise; SIS devices (superconductor); submillimeter wave mixers; superconducting integrated circuit;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2010.2096493

Filename

5682053