Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Fabrication and Characterization of Nb-Al/Al2O3-Nb Superconductor-Insulator-Superconductor Devices with NbTiN Based Tuning Circuits for the HIFI Instrument on the Herschel Space Telescope

S. Glenz

Published Jan 1, 2005• 0 citations
OpenAlex

Related papers

Design and analysis of a broadband SIS-mixer for the Heterodyne Instrument for the Far Infrared (HIFI) on the Herschel Space Observatory

R. Teipen

In this thesis the design and analysis of SIS-mixers (SIS: superconductor-isolator-superconductor) for the use as low-noise and broad-band detectors in the submm-region for astronomical observations is described. The SIS-mixers have been developed for the frequency band 2 (636-802 GHz) of the Heterodyne Instrument for the Far Infrared (HIFI) on ESA’s space-observatory Herschel. The required performance baseline has been defined by the HIFI-consortium in terms of the estimated noise temperature contribution of the mixer to be 110 K at 636 GHz and 150 K at 802 GHz. In the frequency region between 80 GHz and 900 GHz Heterodyne SIS mixers are established as the best devices for low noise mixing with a high spectral resolution (mixing of the signal radiation with local oscillator, LO). For the HIFI band 2 mixers, the technology of Nb/Al-Al2O3/Nb-junctions has been used with junction areas of 0.5-1.0 um2, a target value for the current density jc of 15 kA/cm2 and a gap-voltage of 2.75-2.77 mV. For the compensation of the SIS-junction’s intrinsic capacitance and the optimized power coupling to the tunnel junction, two types of matching circuits have been theoretically modelled and experimentally studied: (1) three-step transformer single junction devices and (2) double-junction devices. This has been done for two material combinations: for an all-superconductive micro strip NbTiN/SiO2/Nb, and for the superconductor/normal-conductor combination NbTiN/SiO2/Al...

•Jan 1, 2006•1 citation

Integration and Characterisation of Superconducting HEB Mixers for the Herschel Space Observatory

Therese Berg

•Jan 1, 2005•0 citations

NbTiN Based Tuning Structures for Broadband Nb-Al 2 O >3 -Nb SIS Mixers from 640 GHz-800 GHz

S. Glenz, Sybille Haas, Cornelia E. Honingh +1 more

We present measurements with a prototype waveguide SIS mixer for band 2 (640 GHz – 800 GHz) of HIFI (Heterodyne Instrument for FIRST). The Nb/Al2O3/Nb junctions have an RnA product from 12–18 Ωμm. These junctions are embedded in microstrip circuits tuning out the device capacitance using a NbTiN ground layer and various top conductor materials such as NbTiN, Nb and Al. The NbTiN films are fabricated by DC magnetron sputtering which is optimized for a minimum value of the DC resistivity and for a high critical temperature by varying the sputter pressure, sputter power and Ar:N2 flow. Typical NbTiN film parameters for device fabrication are ρ = 120 μΩcm and Tc = 14.5 K. The best uncorrected noise temperatures we measured so far are for devices with NbTiN/SiO2/Nb tuning. At 4.2 K bath temperature, a standard Yfactor measurement yields uncorrected receiver noise temperatures of 350 K at 642 GHz and 500 K at 810 GHz for 1.5 GHz intermediate frequency. We discuss the effect of the various tuning circuit materials on the mixer performance. In addition, measurements at IF’s between 4 GHz and 8 GHz will be presented.

Softwaretechnik-Trends•Dec 1, 2001•0 citations

NbTiN-Based THz SIS Mixers for the Herschel Space Observatory

Brian Douglas Jackson

•Jun 8, 2005•6 citations

Fabrication of high quality Nb/Al/AlOx/Nb stacked Josephson junctions

Paola Barbara, G. Costabile

Physica B Condensed Matter•Feb 1, 1994•3 citations

Niobium titanium nitride-based superconductor-insulator-superconductor mixers for low-noise terahertz receivers

Brian D. Jackson, Gert J. de Lange, T. Zijlstra +3 more

Integrating NbTiN-based microstrip tuning circuits with traditional Nb superconductor-insulator-superconductor (SIS) junctions enables the low-noise operation regime of SIS mixers to be extended from below 0.7to1.15THz. In particular, mixers incorporating a NbTiN∕SiO2∕NbTiN microstrip tuning circuit offer low-noise performance below 0.8–0.85THz, although their sensitivities drop significantly at higher frequencies. Furthermore, a microstrip geometry in which NbTiN is used as the ground plane material only (NbTiN∕SiO2∕Al) yields significant improvements in the sensitivities of SIS mixers operating up to 1.15THz, with an upper operating frequency that depends upon the quality of the NbTiN layer, and thus its deposition process. Films deposited at room temperature have Tc=14.4K and ρn,20K∼60μΩcm, and offer low-noise performance up to 1THz, whereas films deposited at 400°C have Tc=16K and ρn,20K∼110μΩcm, and offer low-noise performance up to 1.15THz. Taken together, these results demonstrate that the high-frequency surface resistance of a NbTiN layer depends upon the film’s structural properties. Most significantly, the drop in performance that is seen at F>1THz in mixers incorporating NbTiN ground planes deposited at room temperature is attributed to nonhomogeneities in the structural and electrical properties of these films, as is the poor performance of mixers that incorporate NbTiN wiring layers at F>0.85THz. The development of these NbTiN-based microstrip tuning circuits will enable the production of low-noise SIS mixers for the 0.8–0.96- and 0.96–1.12-THz frequency bands of the Heterodyne Instrument for the Far Infrared on board the European Space Agency’s Herschel Space Observatory.

Journal of Applied Physics•May 25, 2005•29 citations
In this thesis the design and analysis of SIS-mixers (SIS: superconductor-isolator-superconductor) for the use as low-noise and broad-band detectors in the submm-region for astronomical observations is described. The SIS-mixers have been developed for the frequency band 2 (636-802 GHz) of the Heterodyne Instrument for the Far Infrared (HIFI) on ESA’s space-observatory Herschel. The required performance baseline has been defined by the HIFI-consortium in terms of the estimated noise temperature contribution of the mixer to be 110 K at 636 GHz and 150 K at 802 GHz. In the frequency region between 80 GHz and 900 GHz Heterodyne SIS mixers are established as the best devices for low noise mixing with a high spectral resolution (mixing of the signal radiation with local oscillator, LO). For the HIFI band 2 mixers, the technology of Nb/Al-Al2O3/Nb-junctions has been used with junction areas of 0.5-1.0 um2, a target value for the current density jc of 15 kA/cm2 and a gap-voltage of 2.75-2.77 mV. For the compensation of the SIS-junction’s intrinsic capacitance and the optimized power coupling to the tunnel junction, two types of matching circuits have been theoretically modelled and experimentally studied: (1) three-step transformer single junction devices and (2) double-junction devices. This has been done for two material combinations: for an all-superconductive micro strip NbTiN/SiO2/Nb, and for the superconductor/normal-conductor combination NbTiN/SiO2/Al...
We present measurements with a prototype waveguide SIS mixer for band 2 (640 GHz – 800 GHz) of HIFI (Heterodyne Instrument for FIRST). The Nb/Al2O3/Nb junctions have an RnA product from 12–18 Ωμm. These junctions are embedded in microstrip circuits tuning out the device capacitance using a NbTiN ground layer and various top conductor materials such as NbTiN, Nb and Al. The NbTiN films are fabricated by DC magnetron sputtering which is optimized for a minimum value of the DC resistivity and for a high critical temperature by varying the sputter pressure, sputter power and Ar:N2 flow. Typical NbTiN film parameters for device fabrication are ρ = 120 μΩcm and Tc = 14.5 K. The best uncorrected noise temperatures we measured so far are for devices with NbTiN/SiO2/Nb tuning. At 4.2 K bath temperature, a standard Yfactor measurement yields uncorrected receiver noise temperatures of 350 K at 642 GHz and 500 K at 810 GHz for 1.5 GHz intermediate frequency. We discuss the effect of the various tuning circuit materials on the mixer performance. In addition, measurements at IF’s between 4 GHz and 8 GHz will be presented.
Integrating NbTiN-based microstrip tuning circuits with traditional Nb superconductor-insulator-superconductor (SIS) junctions enables the low-noise operation regime of SIS mixers to be extended from below 0.7to1.15THz. In particular, mixers incorporating a NbTiN∕SiO2∕NbTiN microstrip tuning circuit offer low-noise performance below 0.8–0.85THz, although their sensitivities drop significantly at higher frequencies. Furthermore, a microstrip geometry in which NbTiN is used as the ground plane material only (NbTiN∕SiO2∕Al) yields significant improvements in the sensitivities of SIS mixers operating up to 1.15THz, with an upper operating frequency that depends upon the quality of the NbTiN layer, and thus its deposition process. Films deposited at room temperature have Tc=14.4K and ρn,20K∼60μΩcm, and offer low-noise performance up to 1THz, whereas films deposited at 400°C have Tc=16K and ρn,20K∼110μΩcm, and offer low-noise performance up to 1.15THz. Taken together, these results demonstrate that the high-frequency surface resistance of a NbTiN layer depends upon the film’s structural properties. Most significantly, the drop in performance that is seen at F>1THz in mixers incorporating NbTiN ground planes deposited at room temperature is attributed to nonhomogeneities in the structural and electrical properties of these films, as is the poor performance of mixers that incorporate NbTiN wiring layers at F>0.85THz. The development of these NbTiN-based microstrip tuning circuits will enable the production of low-noise SIS mixers for the 0.8–0.96- and 0.96–1.12-THz frequency bands of the Heterodyne Instrument for the Far Infrared on board the European Space Agency’s Herschel Space Observatory.