SIS Mixer Fabrication for ALMA Band10

Kroug, M.; Endo, Akira; Tamura, Takuya; Noguchi, Takashi; Kojima, Takafumi; Uzawa, Yoshinori; Takeda, M.; Wang, Z.; Shan, Wenlei

doi:10.1109/tasc.2009.2017856

Cited by 17 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The two-junction tuning circuit is employed to compensate the junction capacitances [10]. The fabrication procedure is described elsewhere [11], [12]. In our design, 1.05-μm diameter junctions with a current density of 10 kA/cm 2 are assumed, which is achievable by our standard junction fabrication process.…”

Section: B Terahertz Sis Mixermentioning

confidence: 99%

Tuning Circuit Material for Mass-Produced Terahertz SIS Receivers

Uzawa

Fujii

González

et al. 2015

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

A total of 73 dual polarization superconductorinsulator-superconductor (SIS) receivers for the Atacama Large Millimeter/submillimeter Array (ALMA) have been successfully produced to observe astronomical signals in the frequency band of 787-950 GHz. For the mass production of waveguide SIS mixer chips used in the receivers, we have tested two different compositions of Nb 1−x Ti x N thin films for use in the mixer's superconductor low-loss transmission lines. These components are being fabricated for mass-produced waveguide SIS mixer chips in receivers. One composition was prepared by employing a sputtering target with 20 wt.% Ti and 80 wt.% Nb (x = 0.2), and the other was prepared with a target composed of 30 wt.% Ti and 70 wt.% Nb (x = 0.3). Both films are deposited using dc magnetron sputtering on quartz substrates. We found that the ratio between the superconducting energy gap and the critical temperature (2Δ/k B T C ) of the Nb 0.8 Ti 0.2 N films is larger than that of the Nb 0.7 Ti 0.3 N films. Since we obtained better sensitivities in the SIS mixers using the Nb 0.8 Ti 0.2 N films, they were used to produce all the receivers. These showed excellent performance complying with the stringent ALMA specifications.

show abstract

Section: B Terahertz Sis Mixermentioning

confidence: 99%

Tuning Circuit Material for Mass-Produced Terahertz SIS Receivers

Uzawa

Fujii

González

et al. 2015

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The fabrication procedure was described by Kroug et al. (2009). In our design, junctions of >1 μm diameter and with a current density ( J C ) of 10 kA/cm 2 were adopted, which is achievable using our standard junction fabrication process.…”

Section: Alma Band 10 Receiversmentioning

confidence: 99%

“…Nb/AlOx/Nb junctions and NbTiN/ SiO 2 /Al microstrip lines were fabricated on the quartz substrates, and a two-junction tuning circuit was employed to compensate the junction capacitances (Zmuidzinas et al, 1994). The fabrication procedure was described by Kroug et al (2009). In our design, junctions of >1 μm diameter and with a current density (J C ) of 10 kA/cm 2 were adopted, which is achievable using our standard junction fabrication process.…”

Section: Sis Mixer-chip Designmentioning

confidence: 99%

Superconducting Receiver Technologies Supporting ALMA and Future Prospects

et al. 2021

Self Cite

View full text Add to dashboard Cite

The Atacama Large Millimeter/submillimeter Array (ALMA) is the most sensitive ground-based radio astronomical telescope (see Figure 1) (ALMA observatory; URL: http://www.almaobservatory.org). Located in the Atacama Desert, 5,000 m above sea level in northern Chile, South America, it is a collaboration between East Asia, Europe, and North America. ALMA consists of fifty-four 12-m-diameter antennas and twelve 7-m-diameter antennas. The observation frequencies range from 35 GHz (millimeter waves) to 950 GHz (submillimeter waves). With such radio frequency (RF) observations, it is possible to capture the amplitudes and phases of signals from astronomical objects and by performing a proper interference of those signals, a single large synthesized radio telescope can be formed. This method is called aperture synthesis and was developed by radio astronomer Martin Ryle at Cambridge University (Ryle, 1975), for which he was awarded the Nobel Prize in Physics in 1974. The spatial angular resolution is determined by the antenna array configuration and observation frequency. The distance between ALMA antennas can be extended up to 16 km, allowing a maximum angular resolution of less than 0.01″, which is why the term "large" is used in the name. The achievable angular resolution of ALMA is 10 times higher than those of the Subaru Telescope and Hubble Space Telescope and up to 100 times higher than those of the existing millimeter/submillimeter telescopes.ALMA also offers unpreceded sensitivity. Owing to its large collecting area of over 6,600 m 2 and highly sensitive receivers using superconductor-insulator-superconductor (SIS) mixers along with high-electron-mobility transistor (HEMT) amplifiers, ALMA has a sensitivity 2 orders of magnitude better than those of the existing radio telescopes. Most of the SIS mixers in ALMA utilize superconducting niobium (Nb)

show abstract

“…To eliminate or partly reduce the loss and dispersion originating from the Cooper-pair breaking, we may use superconducting films with higher gap voltage or normal metal films such as Al. For example, the ALMA band-10 (beyond 0.7 THz) SIS mixer combines Nb SIS junctions and an integrated NbTiN/SiO 2 /Al tuning circuit [13]. Superconducting thin-film microstrip lines are characterized by combining the classical transmission line theory and Mattis-Bardeen theory addressing the complex conductivity of superconducting films [14].…”

Section: Superconducting Sis Tunnel Junction Mixersmentioning

confidence: 99%

Development of superconducting mixers for THz astronomy

Shi

2011

Sci. China Inf. Sci.

View full text Add to dashboard Cite

The terahertz (THz) regime, loosely defined as 0.1-10 THz, is the last frequency window to be fully explored in astronomy. In particular, it is a regime in which there are rich molecular rotation lines and atomic fine structure lines. They are very important tracers for studying the dynamics of astronomical objects such as stars and planetary systems. Observing those spectral lines usually makes use of coherent detectors (i.e., heterodyne mixers). With sensitivity approaching the quantum limit, superconducting mixers have become the coherent detector of choice in THz astronomy. In this paper we mainly introduce the superconducting mixers developed at Purple Mountain Observatory and those for international collaborative projects.

show abstract

SIS Mixer Fabrication for ALMA Band10

Cited by 17 publications

References 11 publications

Tuning Circuit Material for Mass-Produced Terahertz SIS Receivers

Tuning Circuit Material for Mass-Produced Terahertz SIS Receivers

Superconducting Receiver Technologies Supporting ALMA and Future Prospects

Development of superconducting mixers for THz astronomy

Contact Info

Product

Resources

About