| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
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Towards Multi-Pixel Heterodyne Terahertz Receivers
- 2011
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Ingår i: Proceedings of the 22nd International Symposium on Space Terahertz Technology, Tucson, AZ, USA, April 26-28, 2011. ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Terahertz multi-pixel heterodyne receivers introduce multiple challenges for their implementation, mostly due to the extremely small dimensions of all components and even smaller tolerances in terms of alignment, linear dimensions and waveguide component surface quality. In this manuscript, we present a concept of terahertz multi-pixel heterodyne receiver employing optical layout using polarization split between the LO and RF. The frontend is based on a waveguide balanced HEB mixer for the frequency band 1.6 – 2.0 THz. The balanced HEB mixer follows the layout of earlier demonstrated APEX T2 mixer. However for the mixer presented here, we implemented splitblock layout offering minimized lengths of all waveguides and thus reducing the associated RF loss. The micromachining methods employed for producing the mixer housing and the HEB mixer chip are very suitable for producing multiple structures and hence are in-line with requirements of multi-pixel receiver technology. The demonstrated relatively simple mounting of the mixer chip with self-aligning should greatly facilitate the integration of such multi-channel receiver.
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| 2. |
- Desmaris, Vincent, 1977, et al.
(författare)
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Terahertz components packaging using integrated waveguide technology
- 2011
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Ingår i: 2011 IEEE MTT-S International Microwave Workshop on Millimeter Wave Integration Technologies, IMWS 2011, Sitges 15 September 2011 through 16 September 2011. - 9781612849652 ; , s. 81-84
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Konferensbidrag (refereegranskat)abstract
- We present an integrated waveguide based packaging solution compatible with different THz component technologies, both for room temperature and cryogenic operations, employing space-qualified wire-bonding for electrical contacts. The proposed waveguide packaging relies on the combination of all-metal micro-machined THz waveguide and active component chip layouts suitable for the realization of systems from 200 up to 5000 GHz. It provides possibility of making 3-dimensional structures via facilitating of multi-level (layered) designs. The surface roughness of the fabricated THz waveguide structure was demonstrated to be 20 nm, while a 2 μm alignment accuracy of the active component chip was verified. © 2011 IEEE.
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| 3. |
- Desmaris, Vincent, 1977, et al.
(författare)
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Waveguide Packaging Technology for THz Components and Systems
- 2011
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Ingår i: Proceedings of 6th ESA Workshop on Millimetre-Wave Technology and Applications, May 23-25, 2011, Espoo, Finland.
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Konferensbidrag (refereegranskat)abstract
- We present an integrated THz waveguide packaging solution based on the combination of all-metal micro-machined THz waveguide technology and active component chip layouts suitable for the realization of systems from 200 up to 5000 GHz. This packaging solution is compatible with different THz component technologies, for room temperature and cryogenic operations and employs space-qualified wire-bonding for electrical contacting. The THz waveguide packaging provides possibility of making 3-dimensional structures via facilitating of multi-level (layered) designs. The surface roughness of the fabricated THz waveguide structure was demonstrated to be 20 nm, while the alignment accuracy of the active component chip was measured to be about 2 μm. Some of the demonstrators are already in used, at.e.g., APEX telescope in the SHeFI receiver.
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| 4. |
- Dochev, Dimitar Milkov, 1981, et al.
(författare)
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A Technology Demonstrator for 1.6–2.0 THz Waveguide HEB Receiver with a Novel Mixer Layout
- 2011
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Ingår i: Journal of Infrared, Millimeter, and Terahertz Waves. - : Springer Science and Business Media LLC. - 1866-6892 .- 1866-6906. ; 32:4, s. 451-465
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present our studies on a technology demonstrator for a balanced waveguide hot-electron bolometer (HEB) mixer operating in the 1.6–2.0 THz band. The design employs a novel layout for the HEB mixer combining several key technologies: all-metal THz waveguide micromachining, ultra-thin NbN film deposition and a micromachining of a silicon-on-insulator (SOI) substrate to manufacture the HEB mixer. In this paper, we present a novel mixer layout that greatly facilitates handling and mounting of the mixer chip via self-aligning as well as provides easy electrical interfacing. In our opinion, this opens up a real prospective for building multi-pixel waveguide THz receivers. Such receivers could be of interest for SOFIA, possible follow up of the Herschel HIFI, and even for ground based telescopes yet over limited periods of time with extremely dry weather (PWV less than 0.1 mm).
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| 5. |
- Dochev, Dimitar Milkov, 1981, et al.
(författare)
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Growth and characterization of epitaxial ultra-thin NbN films on 3C-SiC/Si substrate for terahertz applications
- 2011
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Ingår i: Superconductor Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 24:3, s. 035016 (6pp)-
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Tidskriftsartikel (refereegranskat)abstract
- We report on electrical properties and microstructure of epitaxial thin NbN films grown on 3C-SiC/Si substrates by means of reactive magnetron sputtering. A complete epitaxial growth at the NbN/3C-SiC interface has been confirmed by means of high resolution transmission electron microscopy (HRTEM) along with x-ray diffractometry (XRD). Resistivitymeasurements of the films have shown that the superconducting transition onset temperature (TC) for the best specimen is 11.8 K. Using these epitaxial NbN films, we have fabricated submicron-size hot-electron bolometer (HEB) devices on 3C-SiC/Si substrate and performed their complete DC characterization. The observed critical temperature TC = 11.3 K and critical current density of about 2.5 MA cm−2 at 4.2 K of the submicron-size bridges were uniform across the sample. This suggests that the deposited NbN films possess the necessary homogeneity to sustain reliable hot-electron bolometer device fabrication for THz mixer applications.
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| 6. |
- Pavolotskiy, Alexey, 1968, et al.
(författare)
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Aging- and annealing-induced variations in Nb/Al-AlOx/Nb tunnel junction properties
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:2, s. 024502-
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present studies of room temperature aging and annealing of Nb/Al–AlOx/Nb tunnel junctions with the size of 2–3 μm2. We observed a noticeable drop of junction normal resistance Rn unusually combined with increase in subgap resistance Rj as a result of aging. Variation in both Rn and Rj are subject to the junction size effect. An effect of aging history on the junction degradation after consequent annealing was discovered. Discussion and interpretation of the observed phenomena are presented in terms of structural ordering and reconstruction in the AlOx layer, driven by diffusion flows enhanced due to stress relaxation processes in the Al layer interfacing the AlOx layer.
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| 7. |
- Pavolotskiy, Alexey, 1968, et al.
(författare)
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Nb/Al-AlOx/Nb Junction Properties' Variations Due to Storage and Mounting
- 2011
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Ingår i: PROCEEDINGS OF THE 22ND INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY.
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Konferensbidrag (refereegranskat)abstract
- We report studies of room temperature aging and annealing of Nb/Al-AlO x /Nb tunnel junctions with a 2. . . 3 sq.µmsize. We observed a noticeable drop of the junction normal resistance Rn unusually combined with increase of subgap resistance Rj as a result of aging. Changes of Rj occur at sufficiently shorter time scale than that of Rn. Variation of both Rn and Rj depend on the junction size. An effect of aging history on the junction degradation after consequent annealing was discovered. We suggest that the observed junction aging andannealing behavior could be explained by diffusional ordering and structural reconstruction in the tunnel AlOx barrier. The diffusion driving such structural ordering and reconstruction of the AlO x tunnel layer is enhanced due to the intrinsic stress relaxation (creep) processes in the underlying Al layer. Also, we discuss the influence of dicing the wafer into the single mixer chip on the junction aging behavior.
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