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Author Finkel, M.; Thierschmann, H.; Galatro, L.; Katan, A. J.; Thoen, D. J.; de Visser, P. J.; Spirito, M.; Klapwijk, T. M.
Title Performance of THz components based on microstrip PECVD SiNx technology Type Journal Article
Year (down) 2017 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.
Volume 7 Issue 6 Pages 765-771
Keywords transmission line measurements, power transmission lines, dielectrics, couplers, submillimeter wave circuits, coplanar waveguides, micromechanical devices
Abstract We present a performance analysis of passive THz components based on Microstrip transmission lines with a 2-μmthin plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNX) dielectric layer. A set of thru-reflect-line calibration structures is used for basic transmission line characterizations. We obtain losses of 9 dB/mm at 300 GHz. Branchline hybrid couplers are realized that exhibit 2.5-dB insertion loss, 1-dB amplitude imbalance, and -26-dB isolation, in agreement with simulations. We use the measured center frequency to determine the dielectric constant of the PECVD SiN x , which yields 5.9. We estimate the wafer-to-wafer variations to be of the order of 1%. Directional couplers are presented which exhibit -12-dB transmission to the coupled port and -26 dB to the isolated port. For transmission lines with 5-μm-thin silicon nitride (SiN x ), we observe losses below 4 dB/mm. The thin SiN x dielectric membrane makes the THz components compatible with scanning probe microscopy cantilevers allowing the application of this technology in on-chip circuits of a THz near-field microscope.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2156-342X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1294
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Author Shcherbatenko, M.; Tretyakov, I.; Lobanov, Yu.; Maslennikov, S. N.; Kaurova, N.; Finkel, M.; Voronov, B.; Goltsman, G.; Klapwijk, T. M.
Title Nonequilibrium interpretation of DC properties of NbN superconducting hot electron bolometers Type Journal Article
Year (down) 2016 Publication Appl. Phys. Lett. Abbreviated Journal
Volume 109 Issue 13 Pages 132602
Keywords HEB mixer, contacts
Abstract We present a physically consistent interpretation of the dc electrical properties of niobiumnitride (NbN)-based superconducting hot-electron bolometer mixers, using concepts of nonequilibrium superconductivity. Through this, we clarify what physical information can be extracted from the resistive transition and the dc current-voltage characteristics, measured at suitably chosen temperatures, and relevant for device characterization and optimization. We point out that the intrinsic spatial variation of the electronic properties of disordered superconductors, such as NbN, leads to a variation from device to device.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1107
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Author Finkel, M.; Thierschmann, H. R.; Galatro, L.; Katan, A. J.; Thoen, D. J.; de Visser, P. J.; Spirito, M.; Klapwijk, T. M.
Title Branchline and directional THz coupler based on PECVD SiNx-technology Type Conference Article
Year (down) 2016 Publication 41st IRMMW-THz Abbreviated Journal 41st IRMMW-THz
Volume Issue Pages
Keywords microstrip, fixtures, coplanar waveguides, couplers, standards, probes, dielectrics
Abstract A fabrication technology to realize THz microstrip lines and passive circuit components is developed and tested making use of a plasma-enhanced chemical vapor deposition grown silicon nitride (PECVD SiNx) dielectric membrane. We use 2 μm thick SiNx and 300 nm thick gold layers on sapphire substrates. We fabricate a set of structures for thru-reflect-line (TRL) calibration, with the reflection standard implemented as a short through the via. We find losses of 9.5 dB/mm at 300 GHz for a 50 Ohm line. For a branchline coupler we measure 2.5 dB insertion loss, 1 dB amplitude imbalance and 21 dB isolation. Good control over the THz lines parameters is proven by similar performance of a set of 5 structures. The directional couplers show -14 dB transmission to the coupled port, -24 dB to the isolated port and -25 dB in reflection. The SiNx membrane, used as a dielectric, is compatible with atomic force microscopy (AFM) cantilevers allowing the application of this technology to the development of a THz near-field microscope.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2162-2035 ISBN 978-1-4673-8485-8 Medium
Area Expedition Conference
Notes Approved no
Call Number 7758586 Serial 1295
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Author Lobanov, Y.; Shcherbatenko, M.; Finkel, M.; Maslennikov, S.; Semenov, A.; Voronov, B. M.; Rodin, A. V.; Klapwijk, T. M.; Gol'tsman, G. N.
Title NbN hot-electron-bolometer mixer for operation in the near-IR frequency range Type Journal Article
Year (down) 2015 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 25 Issue 3 Pages 2300704 (1 to 4)
Keywords HEB mixer, IR, optical antenna
Abstract Traditionally, hot-electron-bolometer (HEB) mixers are employed for THz and “super-THz” heterodyne detection. To explore the near-IR spectral range, we propose a fiber-coupled NbN film based HEB mixer. To enhance the incident-light absorption, a quasi-antenna consisting of a set of parallel stripes of gold is used. To study the antenna effect on the mixer performance, we have experimentally studied a set of devices with different size of the Au stripe and spacing between the neighboring stripes. With use of the well-known isotherm technique we have estimated the absorption efficiency of the mixer, and the maximum efficiency has been observed for devices with the smallest pitch of the alternating NbN and NbN-Au stripes. Also, a proper alignment of the incident Eâƒ<2014>-field with respect to the stripes allows us to improve the coupling further. Studying IV-characteristics of the mixer under differently-aligned Eâƒ<2014>-field of the incident radiation, we have noticed a difference in their shape. This observation suggests that a difference exists in the way the two waves with orthogonal polarizations parallel and perpendicular Eâƒ<2014>-field to the stripes heat the electrons in the HEB mixer. The latter results in a variation in the electron temperature distribution over the HEB device irradiated by the two waves.
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Notes Approved no
Call Number Serial 952
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Author Seliverstov, S.; Maslennikov, S.; Ryabchun, S.; Finkel, M.; Klapwijk, T. M.; Kaurova, N.; Vachtomin, Yu.; Smirnov, K.; Voronov, B.; Goltsman, G.
Title Fast and sensitive terahertz direct detector based on superconducting antenna-coupled hot electron bolometer Type Journal Article
Year (down) 2015 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 25 Issue 3 Pages 2300304
Keywords HEB detector responsivity, HEB model, numerical calculations, numerical model
Abstract We characterize superconducting antenna-coupled hot-electron bolometers for direct detection of terahertz radiation operating at a temperature of 9.0 K. The estimated value of responsivity obtained from lumped-element theory is strongly different from the measured one. A numerical calculation of the detector responsivity is developed, using the Euler method, applied to the system of heat balance equations written in recurrent form. This distributed element model takes into account the effect of nonuniform heating of the detector along its length and provides results that are in better agreement with the experiment. At a signal frequency of 2.5 THz, the measured value of the optical detector noise equivalent power is 2.0 × 10-13 W · Hz-0.5. The value of the bolometer time constant is 35 ps. The corresponding energy resolution is about 3 aJ. This detector has a sensitivity similar to that of the state-of-the-art sub-millimeter detectors operating at accessible cryogenic temperatures, but with a response time several orders of magnitude shorter.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 953
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