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Further improvements and developments:  Optimization of ultra-thin NbN (and other nitrides or cuprates) superconducting films on large wafers and of patterned.

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Presentation on theme: "Further improvements and developments:  Optimization of ultra-thin NbN (and other nitrides or cuprates) superconducting films on large wafers and of patterned."— Presentation transcript:

1 Further improvements and developments:  Optimization of ultra-thin NbN (and other nitrides or cuprates) superconducting films on large wafers and of patterned devices adapted to Hot Electron Bolometer SSPD.  Development of new integrated digital applications of NbN and nitrides devices integrated with NbN RSFQ circuits on silicon wafers (see talk 3EA04) Fabrication and characterization of superconducting NbN epitaxial ultrathin layers and nanowires R. Espiau de Lamaestre 1, E. Bellet-Amalric 1, R. Setzu 1, J-C. Villégier 1, J. Claudon 2,1, J-Ph. Poizat 2,1, C. Delacour 2, V. Bouchiat 2, L. Méchin 3, P. Moretti 4, 1 CEA-Grenoble (France), 2 CNRS-Grenoble (France), 3 ENSI-Caen (France), 4 UCB-Lyon (France) Perspectives Epitaxial superconducting film deposition conditions Typical DC-magnetron sputtering conditions and characterization of a 3 to 100 nm film epitaxially grown on R-plane sapphire or MgO 2MM02 Structuration of NbN layers for photon detection Applied Superconductivity Conference 2006 200 nm  (T), normalized conductance (2  (0) = 4.3 meV) using LT- STM and Jc (T) characterisations and surface imaging (2x2 µm 2 ) showing a good uniformity and small roughness in a 3.4 nm thick NbN on 3inch R-plane sapphire. NbN (100) Epitaxial growth of 4 nm NbN on Si (100) using either an ultrathin TaNx (~1 nm) silicide or an YSZ buffer layer Reciprocal space section in both plane chosen for this study. Epitaxial relation: Experimental limits are materialized by light (wavelength) and dark (plane opaque sample) grey. Example of Mo 2 N cubic nitride thin film (~10 nm thick) epitaxially grown of on R-plane Sapphire HR-TEM cross-section image of an ultrathin NbN film grown at 600°C on R-plane sapphire M.Faucher et al. Physica C, 368, 211, (2002) NbN (3.4 nm thick) nano-bridges patterned by e-Beam lithography Characterization of 3-7 nm epi-NbN films on R-plane sapphire and on Si (100) 6.6nm epi-NbN on R-sapphire. Reciprocal space map (units: 2  / ) around the awaited position (Qx=-3.05; Qz=4.82, green circle) of the 004 diffraction peak of NbN. Time (ns)  =-40.2° 100nm NbN line spaced by 100nm. E beam litho,PMMA Very thin (2.5-10nm thick) epi-NbN superconducting layers with large Tc and large Jc are grown by dc- magnetron sputtering in a controlable way on heated 3' and 4' R-plane Sapphire, YSZ or silicide buffered silicon (100) and MgO (100). Very thin (~1nm) AlN overlayer are insuring storage without degradation. (135) NbN growth on top of R-plane Sapphire at 600°C is directly observed by XRD for very thin layers. E-beam lithography or AFM tip anodization are used for patterning robust NbN nanowires less than 100nm width & meander SSPD. Stability of NbN layers under proton irradiation allows the realization of buried optical wave-guide under NbN stripes. Such NbN nanolayers and SSPD integrated devices are applied to photon detection, THz mixers and fast RSFQ circuit interfaces. epi-YSZ is deposited by PLD AFM lithography limited by the tip radius ~30nm Narrow and dense (80% surface) 2 µm NbN NbNOx Oxide 5µm Observation of SSPD single photon @ ~1µm time response of the NbN (3.4 nm thick) NbN 3.4 nm strips before and after proton irradiation: 1 MeV/1.75.1016 ions/cm2 + 0.95 MeV/1.75.1016 ions/cm2 Same 6.6 nm NbN sample as for XRD


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