Publications (32)29.62 Total impact
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Conference Proceeding: Superconducting Integrated THz Receiver
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ABSTRACT: A Superconducting Integrated Receiver (SIR) developed for balloon borne instrument TELIS covers frequency range 450-650 GHz. The DSB noise temperature was measured as low as 120 K. The SIR application for high resolution spectroscopy of breathed out air has been proven.Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2010 35th International Conference on; 10/2010 -
Article: Implementation of superconductor-ferromagnet-superconductor pi-shifters in superconducting digital and quantum circuits
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ABSTRACT: The difference between the phases of superconducting order parameter plays in superconducting circuits the role similar to that played by the electrostatic potential difference required to drive a current in conventional circuits. This fundamental property can be altered by inserting in a superconducting circuit a particular type of weak link, the so-called Josephson $\pi$-junction having inverted current-phase relation and enabling a shift of the phase by $\pi$. We demonstrate the operation of three superconducting circuits -- two of them are classical and one quantum -- which all utilize such $\pi$-phase shifters realized using superconductor-ferromagnet-superconductor sandwich technology. The classical circuits are based on single-flux-quantum cells, which are shown to be scalable and compatible with conventional niobium-based superconducting electronics. The quantum circuit is a $\pi$-phase biased qubit, for which we observe coherent Rabi oscillations and compare the measured coherence time with that of conventional superconducting phase qubits. Comment: 14 pages, 4 figures05/2010; -
Article: A cryogenic phase locking loop system for a superconducting integrated receiver
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ABSTRACT: The authors present a new cryogenic device, an ultrawideband cryogenic phase locking loop system (CPLL). The CPLL was developed for phase locking of a flux-flow oscillator (FFO) in a superconducting integrated receiver (SIR) but can be used for any cryogenic terahertz oscillator. The key element of the CPLL is the cryogenic phase detector (CPD), a recently proposed new superconducting element. The CPD is an innovative implementation of a superconductor– insulator–superconductor tunnel junction. All components of the CPLL reside inside a cryostat at 4.2 K, with the loop length of cables 50 cm and the total loop delay 4.5 ns. So small a delay results in a CPLL synchronization bandwidth as wide as 40 MHz and allows phase locking of more than 60% of the power emitted by the FFO, even for FFO linewidths of about 11 MHz. This percentage of phase locked power is three times that achieved with conventional room temperature PLLs. Such an improvement enables reducing the FFO phase noise and extending the SIR operation range.Supercond. Sci. Technol. Supercond. Sci. Technol. 01/2009; 2221(22):85012-4. -
Article: Superconducting integrated on-board spectrometer of the submillimeter-wave range for atmospheric research
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ABSTRACT: We present the latest results of developing and implementing a fully superconducting integrated receiver of the submillimeter-wave range on the basis of the superconductor-insulator-superconductor tunnel junction. Characteristics of a new-generation unique device operated in the frequency range 500–600 GHz and intended for atmospheric research onboard a high-altitude balloon within the framework of the international TELIS project are given. This frequency range comprises spectral lines of many chlorine-containing compounds, the registration of which is a major problem of the environmental monitoring of the atmosphere. In the process of creating the spectrometer, we developed the technology for manufacturing Nb/AlN/NbN junctions, which made it possible to reduce the emission linewidth of the superconducting local oscillator based on the long Josephson junction and decrease the noise temperature of the receiver. At the same time, the possibility to continuously tune the local-oscillator frequency in the entire operating range was realized.Radiophysics and Quantum Electronics 09/2007; 50(10):847-851. · 0.71 Impact Factor -
Article: Superconducting Integrated Receiver Based on Nb-AlN-NbN-Nb Circuits
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ABSTRACT: The superconducting integrated receiver (SIR) comprising in one chip a superconductor-insulator-superconductor (SIS) mixer and a phase-locked superconducting flux flow oscillator (FFO) is under development for the international project TELIS. To overcome temperature constraints and extend operation frequency of the SIR we have developed and studied Nb-AlN-NbN-Nb circuits with a gap voltage Vg up to 3.7 mV and extremely low leakage currents . Based on these junctions integrated microcircuits comprising FFO and harmonic mixer have been designed, fabricated and tested; the radiation from such circuits has been measured at frequencies up to 700 GHz. Employment of NbN electrode does not result in the appearance of additional noise. For example, FFO linewidth as low as 1 MHz was measured at 600 GHz, that allows us to phase lock up to 92% of the emitted by FFO power and realize very low phase noise about 90 dBc. Preliminary results demonstrated uncorrected DSB noise temperature of the Nb-AlN-NbN SIR below 250 K at frequencies around 600 GHz.IEEE Transactions on Appiled Superconductivity 07/2007; · 1.04 Impact Factor -
Article: Cryogenic Phase Detector for Superconducting Integrated Receiver
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ABSTRACT: New superconducting element, a cryogenic phase detector (CPD) has been proposed and preliminary tested. The CPD is based on a superconductor-insulator-superconductor junction and initially intended for phase locking of a flux-flow oscillator in a superconducting integrated receiver. First results of the CPD development and study are very encouraging; a sinusoidal response of the CPD has been measured at the variation of the phase shift between input signals. Dependences of the output signal and phase response on the CPD bias voltage have been studied; main parameters of this new device are estimated. Important that the CPD output current well above 10 has been measured at the input signal provided by the harmonic mixer of the integrated receiver and amplified by the existing HEMT-amplifier. Due to the large conversion coefficient this current being supplied to the flux-flow oscillator (FFO) control line is sufficient to directly tune FFO frequency. Obtained data demonstrate that the CPD intrinsically could operate with effective bandwidth more than 100 MHz. Preliminary results of the CPD implementation for the FFO phase locking are presented; possible advantages of such combination are discussed.IEEE Transactions on Appiled Superconductivity 07/2007; · 1.04 Impact Factor -
Article: Integrated superconducting spectrometer for atmosphere monitoring
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ABSTRACT: The results of the development of sub-mm Superconducting Integrated Receiver (SIR) for monitoring of the Earth’s atmosphere from high-altitude balloons are presented. The microchip of the superconducting integrated receiver comprising local oscillator based on the long Josephson junction (flux flow oscillator, FFO) is developed and successfully tested. The receiver noise temperature as low as 200 K is measured at a frequency of 650 GHz. The possibility to phase-lock FFO to the reference oscillator, which is vitally important for spectrometer operation, is demonstrated. To ensure the possibility of remote tuning of a phase-locked (PL) SIR onboard a balloon, a number of approaches for the PL SIR automatic computer control are developed and tested. New modifications of the superconducting local oscillator (FFO) are developed, fabricated and tested. The FFO design is optimized for the integrated spectrometer. The FFO linewidth is studied at frequencies of up to 700 GHz using a specially developed technique. A free-running linewidth between 9 and 2 MHz is measured in the frequency range from 500 to 700 GHz. As a result, the spectral ratio of the phased-locked FFO ranges from 35 to 90%. The effect of FFO linewidth imperfections on the retrieval procedure of the atmosphere gas spectra is studied.Radiophysics and Quantum Electronics 09/2005; 48(10):844-850. · 0.71 Impact Factor -
Article: Optimization of the phase-locked flux-flow oscillator for the submm integrated receiver
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ABSTRACT: The Superconducting Integrated Receiver (SIR) comprises in one chip a planar antenna integrated with an SIS mixer, a superconducting Flux Flow Oscillator (FFO) acting as Local Oscillator (LO) and a second SIS harmonic mixer (HM) for FFO phase locking. Free-running FFO linewidth well below 10 MHz is required to ensure phase-locked operation of an SIR. Comprehensive experimental study of the Nb-AlOx-Nb FFO linewidth and other main parameters has been carried out in order to achieve this goal. Essential dependence of the FFO linewidth on its width and idle region dimension has been found. It makes possible an optimization of the FFO design and selection of the best FFO parameters for practical operation of the SIR.IEEE Transactions on Appiled Superconductivity 07/2005; · 1.04 Impact Factor -
Article: A superconducting phase-locked local oscillator for a submillimetre integrated receiver
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ABSTRACT: Comprehensive measurements of the flux flow oscillator (FFO) radiation linewidth are performed using an integrated harmonic SIS mixer; the FFO linewidth and spectral line profile are compared to a theory. An essential dependence of the FFO linewidth on frequency is found; a possible explanation is proposed. The results of the numerical solution of the perturbed sine–Gordon equation qualitatively confirm this assumption. To optimize the FFO design, the influence of the FFO parameters on the radiation linewidth is studied. A novel FFO design at a moderate current density has resulted in a free-running FFO linewidth of about 10 MHz in the flux flow regime up to 712 GHz, limited only by the gap frequency of Nb. This relatively narrow free-running linewidth (along with implementation of a wide-band phase locking loop system) allows continuous phase locking of the FFO in the wide frequency range of 500–710 GHz. These results are the basis for the development of a 550–650 GHz integrated receiver for the terahertz limb sounder (TELIS) intended for atmosphere study and scheduled to fly on a balloon in 2005. We report here also on the design of the second generation of the phase-locked superconducting integrated receiver chip for TELIS.Superconductor Science and Technology 02/2004; 17(5):S127. · 2.66 Impact Factor -
Article: Integrated Superconducting Submillimeter-Wave Receivers
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ABSTRACT: We overview recent achievements in the field of cryogenic submillimeter-wave receivers based on superconductor–insulator–superconductor (SIS) tunnel junctions. The main attention is paid to the novel superconducting integrated receivers (SIRs) with an on-chip superconducting local oscillator. The single-chip microcircuit of the receiver, which integrates a quantum mixer based on the nonlinearity of a quasi-particle current in the SIS junction, a planar superconducting receiving antenna, and a cryogenic local oscillator, is described. Being dc-powered only by batteries, such a microcircuit operates as a submillimeter-wave superheterodyne receiver without any additional microwave equipment. Such receivers are very attractive for radioastronomical research, space communication systems, and monitoring of the environment from satellites, balloons, and special aircraft.A breadboard of a superconducting spectrometer with a phase-locked flux-flow oscillator (FFO) has been developed and tested. A frequency resolution better than 10kHz was reached at a frequency of 365GHz. We describe a balloon-borne 500-650 GHz integrated spectrometer for oblique atmospheric sounding, developed for the international Terahertz Limb Sounder (TELIS) project. The first flight is scheduled for 2005.Radiophysics and Quantum Electronics 07/2003; 46(8):618-630. · 0.71 Impact Factor -
Article: High quality Nb-based tunnel junctions for high frequency and digital applications
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ABSTRACT: A number of new fabrication techniques are developed and optimized in order to fit the requirements of contemporary superconducting electronics. To achieve ultimate performance of integrated submm receivers with operational frequency of 1 THz, tunnel junctions with AlN tunnel barrier having a R<sub>n</sub>S value as low as 1 Ωμm<sup>2</sup> have been developed. High quality characteristics of Nb/AlN/Nb tunnel junctions with R<sub>j</sub>/R<sub>n</sub>=16 and R<sub>n</sub>S=10 Ωμm<sup>2</sup> have been demonstrated. Electron Beam Lithography (EBL) in combination with Chemical Mechanical Polishing (CMP) has been incorporated to produce Nb/AlN/Nb junctions with 0.03 μm<sup>2</sup> area. A new approach to obtain overdamped Nb/AlO<sub>x</sub>/Nb tunnel junctions has been proposed and realized. The dependencies of the main parameters of novel junctions on the current density and circuit geometry have been studied. These junctions may have a good potential in Josephson junction arrays and Single-Flux-Quantum applications (RSFQ).IEEE Transactions on Appiled Superconductivity 07/2003; · 1.04 Impact Factor -
Article: Externally phase-locked flux flow oscillator for submm integrated receivers: achievements and limitations
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ABSTRACT: A Josephson flux flow oscillator (FFO) is the most developed superconducting local oscillator for integration with an SIS mixer in a single-chip submm-wave receiver. Recently, using a new FFO design, a free-running linewidth ≤10 MHz has been measured in the frequency range up to 712 GHz, limited only by the gap frequency of Nb. This enabled us to phase lock the FFO in the frequency range 500-712 GHz where continuous frequency tuning is possible; resulting in an absolute FFO phase noise as low as -80 dBc at 707 GHz. Comprehensive measurements of the FFO radiation linewidth have been performed using an integrated SIS harmonic mixer. The influence of FFO parameters on radiation linewidth, particularly the effect of the differential resistances associated both with the bias current and the applied magnetic field has been studied in order to further optimize the FFO design. A new approach with a self-shielded FFO has been developed and experimentally tested.IEEE Transactions on Appiled Superconductivity 07/2003; · 1.04 Impact Factor -
Article: An integrated receiver with phase-locked superconducting oscillator
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ABSTRACT: A submillimeter heterodyne spectrometer employing a superconducting local oscillator is demonstrated for the first time. The sensor chip comprises a quasioptical double-dipole lens-antenna SIS mixer (T<sub>RX</sub>=250 K at 380 GHz), a Josephson flux-flow oscillator and a SIS harmonic mixer. Room temperature PLL electronics is used with a reference source at 10 GHz. The PLL bandwidth of 10 MHz and the hold range of 3 GHz are estimated for locking at 32-th harmonic of the reference source. The spectral resolution better than 1 MHz and broadening effect of a spectral line of SO<sub>2</sub> gas at 326867 MHz are measured with a laboratory gas cell at 300 K at pressure 0.03 - 0.3 mbar using acousto-optical spectrometer.IEEE Transactions on Appiled Superconductivity 07/2003; · 1.04 Impact Factor -
Article: Texture-related roughness of (Nb,Ti)N sputter-deposited films
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ABSTRACT: We study the properties of (Nb,Ti)N films deposited by reactive magnetron sputtering in an atmosphere of argon and nitrogen at ambient substrate temperature, focusing, in particular, on the technological factors determining film texture and roughness. We find that increasing the adatom energy, while keeping the film chemical composition constant, results in a change of texture from [111] to [100]. Similar changes in film texture are observed as the nitrogen injection decreases for a constant sputtering pressure, indicating that adatom energy is not the only one determining factor. Analyzing the experimental data, it is concluded that nitrogen concentration has a very strong influence on the process of the texture formation, since an increase in nitrogen injection results in an increase in adatom energy, while the film growth is driven toward [111] texturing. Film roughness is strongly related with texture in both experiments, i.e., decreases with an increase in the ratio of [200] and [111] XRD line intensities, indicating that film roughness is determined by crystal habit.IEEE Transactions on Appiled Superconductivity 07/2003; · 1.04 Impact Factor -
Article: Phase-locked Josephson flux flow local oscillator for sub-mm integrated receivers
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ABSTRACT: The Josephson flux flow oscillator (FFO) has proven to be one of the best on-chip local oscillators for heterodyne detection in integrated sub-mm receivers based on SIS mixers. Nb–AlOx–Nb FFOs have been successfully tested from about 120 to 700 GHz (gap frequency of Nb) providing enough power to pump an SIS mixer (about 1 μW at 450 GHz). Both the frequency and the power of the FFO can be dc-tuned. Extensive measurements of the dependence of the free-running FFO linewidth on the differential resistances associated with both the bias current and the control-line current (applied magnetic field) have been performed. The FFO line is Lorentzian both in the resonant regime, on Fiske steps (FSs), and on the flux flow step (FFS). This indicates that internal wide-band noise is dominant. A phenomenological noise model can account for the FFO linewidth dependence on experimental parameters. The narrow free-running FFO linewidth achieved, in combination with the construction of a wide-band phase-locked loop (PLL) system, enable us to phase lock the FFO in the frequency range 490–712 GHz where continuous frequency tuning is possible.Superconductor Science and Technology 11/2002; 15(12):1701. · 2.66 Impact Factor -
Article: Texture formation in sputter-deposited (Nb0.7,Ti0.3)N thin films
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ABSTRACT: We studied the properties of (Nb0.7,Ti0.3)N films deposited by reactive magnetron sputtering in an atmosphere of argon and nitrogen at ambient substrate temperature, with a particular focus on the technological factors that determine film texture. The texture in the nitrides of transition metals determines many processes, including the wear resistance of tool coatings, diffusion in microelectronic devices, and the rate of chemical etching. Thus, since our goal is to use (Nb0.7,Ti0.3)N films in superconducting microelectronic devices, texture control is an essential element of our technology. We find that increasing the total gas pressure, while keeping the film chemical composition constant, results in a decrease in the ratio of the [200] and [111] x-ray diffraction (XRD) line intensities on Θ–2Θ Bragg–Brentano scans. Similar changes in XRD patterns are observed as the nitrogen injection increases for a constant sputtering pressure. In addition, XRD examination shows that some samples have in-plane texture developed due to self-shadowing during growth. Transmission electron microscopy reveals that all of the films consist of textured, elongated grains. Analyzing the experimental data, it is concluded that the thermalization of the sputtering yield determines the process of texture formation in the experiment with pressure variation, with an increase in adatom energy resulting in a change in texture from [111] to [100]. However, adatom energy is not the only determining factor—the nitrogen concentration in the sputtering gas also has a strong impact on the film texture. In particular, despite the fact that an increase in nitrogen injection results in an increase in adatom energy, the film texture is driven toward [111]. © 2002 American Institute of Physics.Journal of Applied Physics 10/2002; 92(9):4999-5005. · 2.17 Impact Factor -
Article: Submillimeter superconducting integrated receivers: Fabrication and yield
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ABSTRACT: Fabrication procedure and yield analysis of superconducting integrated receivers is reported. These chip receivers, apart from the quasi-optical SIS mixers, contain internal local oscillators and associated rf and dc interfaces. Due to both complexity and design requirements of the integrated circuit, certain restrictions are applied to the standard Nb/Al/Al<sub>x</sub>O<sub>y</sub>/Nb SNEAP process. To obtain accurate area for micron-size SIS junctions and thickness for multi-layer SiO<sub>2</sub> insulation, a few solutions and modifications were developed. The possibility of transferring this fabrication process worldwide has been proven experimentallyIEEE Transactions on Appiled Superconductivity 04/2001; · 1.04 Impact Factor -
Article: Low-noise S-band DC SQUID based amplifier
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ABSTRACT: A low-noise rf amplifier based on a dc SQUID (SQA) is tested in the frequency range 3.3-4.1 GHz. A new signal launching system for the SQA rf coupling has been developed and successfully implemented. The following parameters have been measured at 3.65 GHz using a band-pass filter at the input of a single-stage SQA: gain (11.0±1.0) dB, 3 dB bandwidth of 300 MHz and noise temperature (4.0±1.0)K. This figure corresponds to a flux noise S<sub>Φ</sub><sup>½</sup>=0.6 μΦ<sub>0</sub>/Hz<sup>½</sup> and an energy sensitivity ε<sub>i</sub>≈75 h. The input saturation power, P<sub>s</sub>, (1 dB gain compression) is measured for different bandwidths of the input band-pass filter, A corresponding input signal saturation temperature (normalized for a 1 GHz bandwidth) T<sub>SAT</sub><sup>1GHZ </sup>=P<sub>SAT</sub>/k<sub>B</sub> is estimated to be 11.5 K GHz at an SQA bias voltage 27 μV (condition for minimum noise temperature). The dependencies of the SQA gain, noise temperature and saturation level on the operation point are studied. The reason for the SQA saturation is discussedIEEE Transactions on Appiled Superconductivity 04/2001; · 1.04 Impact Factor -
Article: Properties of (Nb0.35, Ti0.15)xNi1−x thin films deposited on silicon wafers at ambient substrate temperature
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ABSTRACT: We have studied the properties of (Nb0.35, Ti0.15)xN1−x films deposited by reactive magnetron sputtering at ambient substrate temperature, focusing in particular on the dependence of film properties on the total sputtering pressure. As the pressure increases we observe a transition in the film structure from the ZT to the Z1 structural zone according to the Thornton classification. In general, the superconducting transition temperature (Tc) and residual resistance ratio have a very moderate dependence on total sputtering pressure, while the film resistivity increases an order of magnitude as the sputtering pressure increases. A wide spectrum of material science techniques is used to characterize the films and to explain the relationship between the sputtering conditions and film properties. Transmission electron microscopy and x-ray diffraction analysis show that 160-nm-thick (Nb0.35, Ti0.15)xN1−x films consist of 20–40 nm grains with good crystallinity. Films sputtered under low pressures have a weak [100] texture, while films sputtered under high pressures have a distinct [111] texture. A stable chemical composition and reduction in film density as the sputtering pressure increases indicate that the change of resistivity in the ZT structural zone is due to a variation in the quenched-in vacancy concentration. In contrast voids on the grain boundaries and vacancies together produce the high film resistivities in the Z1 structural zone. © 2000 American Institute of Physics.Journal of Applied Physics 11/2000; 88(10):5756-5759. · 2.17 Impact Factor -
Article: Source optimization for magnetron sputter-deposition of NbTiN tuning elements for SIS THz detectors
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ABSTRACT: NbTiN is one of the most promising materials for use in the tuning circuits of Nb-based SIS mixers for operating frequencies above the gap frequency of Nb (700 GHz). Device development requires stable and reproducible film properties. In this manuscript we compare the properties of NbTiN films obtained with a sputtering source using balanced and unbalanced magnetic trap configurations. This experiment shows that reducing the effectiveness of the magnetic trap by changing the magnet configuration is equivalent to reducing the sputtering pressure. We also show that it is possible to optimize the configuration of the magnetron magnets to produce stable and reproducible NbTiN films under the same gas pressure and applied power throughout the target lifetime.Superconductor Science and Technology 11/1999; 12(11):736. · 2.66 Impact Factor
Top co-authors
Top Journals
Institutions
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2001–2010
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Moscow State Institute of Radio Engineering, Electronics and Automation
Moscow, Moscow, Russia
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1970–2007
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Russian Academy of Sciences
- Institute of Radioengineering & Electronic
Moscow, Moscow, Russia
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2005
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Netherlands Institute for Radio Astronomy
Dwingeloo, Provincie Drenthe, Netherlands
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2003
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Technische Universiteit Delft
- Faculty of Applied Sciences (AS)
Delft, South Holland, Netherlands
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1999
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University of Groningen
- Zernike Institute for Advanced Materials (ZIAM)
Groningen, Province of Groningen, Netherlands
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