A. Paccagnella

University of Padova, Padua, Veneto, Italy

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Publications (312)276.43 Total impact

  • Source
    Dataset: cellere
  • [Show abstract] [Hide abstract]
    ABSTRACT: Prototypes of DC/DC power and Point of Load (PoL) converters were designed and built with the aim of satisfying the foreseen working parameters of the High Luminosity (HL) LHC experiments, using both Silicon (Si) MOSFETs and/or more recent devices substantiated of better power performance, like Silicon Carbide (SiC) and Gallium Nitride (GaN) transistors. Optimization of their design, based on the comparison between the simulated and measured thermal, electrical and mechanical performance, is in progress, and many improvements with respect to the previous versions are under implementation. We discuss in this paper the results of the last modifications.
    Journal of Instrumentation 02/2014; 9(02):C02017. · 1.66 Impact Factor
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    ABSTRACT: Monte Carlo analysis of hot-electron degradation in AlGaN/GaN high-electron mobility transistors shows that, for gate voltages corresponding to semi-ON bias conditions, the average electron energy has a spatial peak with ${langle}{rm E}_{rm AVE}{rangle}{sim}{1.5}~{rm eV}$ . The peak is located at the edge of the gate. At this location, the carrier versus energy distribution has a large tail extending over 3 eV. When transferred to the lattice, this energy can cause defect dehydrogenation and device degradation. These results are consistent with the experimental data indicating maximum degradation in the semi-ON bias condition.
    IEEE Transactions on Electron Devices 01/2014; 61(5):1316-1320. · 2.06 Impact Factor
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    ABSTRACT: We review ionizing radiation effects in Flash memories, the current dominant technology in the commercial non-volatile memory market. A comprehensive discussion of total dose and single event effects results is presented, concerning both floating gate cells and peripheral circuitry. The latest developments, including new findings on the mechanism underlying upsets due to heavy ions and destructive events, are illustrated.
    IEEE Transactions on Nuclear Science 06/2013; 60(3):1953-1969. · 1.22 Impact Factor
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    ABSTRACT: We studied the occurrence of supply current spikes and destructive events in NAND flash memories under heavy-ion exposure. In addition to broad-beam experiments, we used collimated beams and ion-electron emission microscopy to investigate the phenomena on two types of memories with different feature size. Current spikes on the supply current were observed in both devices, also with collimated beams, whereas destructive events occurred only with broad beam. We show that current spikes do not originate from charge-pump capacitors, as previously suggested, and propose that destructive events are due to the effects of temporally close heavy-ion hits on distinct areas of the tested chips.
    IEEE Transactions on Nuclear Science 01/2013; 60(6):4136-4141. · 1.22 Impact Factor
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    ABSTRACT: We analyzed floating-gate upsets in 25-nm multilevel cell NAND Flash memories irradiated with heavy ions, including alpha particles. Compared to multilevel cell memories of previous generations, these devices show no apparent error dependence on the program level, adherence to the cosine law, and a large number of multiple cell upsets (MCUs). Floating-gate errors were mapped to their physical location, and MCUs were studied as a function of their multiplicity, direction, particle linear energy transfer, irradiation angle, and program level.
    IEEE Transactions on Nuclear Science 01/2013; 60(4):2675-2681. · 1.22 Impact Factor
  • WOCSDICE 2013; 01/2013
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    ABSTRACT: We investigate proton-induced upsets in state-of-the-art NAND Flash memories, down to the 25-nm node. The most striking result is the opposite behavior of Multi-Level Cell (MLC) and Single-Level Cell (SLC) devices, in terms of floating gate error cross section as a function of proton energy. In fact, the cross section increases with proton energy in SLC whereas it decreases in MLC. The reason for this behavior is studied through comparison of heavy-ion data and device simulations. The main factors that determine proton energy dependence are discussed, such as the energy dependence of nuclear cross section between protons and chip materials, the LET, energy, and angular distributions of the generated secondaries, but also the heavy-ion and total dose response of the studied devices. Proton irradiation effects in the control circuitry of NAND Flash memories are shown as well.
    IEEE Transactions on Nuclear Science 01/2013; 60(6):4130-4135. · 1.22 Impact Factor
  • M. Bagatin, S. Gerardin, A. Paccagnella
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    ABSTRACT: The retention of floating gate cells is studied up to one year after heavy-ion exposure, without using accelerated tests. Cross-sections of retention errors and threshold voltage shifts are discussed and compared with previous generation devices. The dependence of retention errors on the program level and irradiation angle is discussed and the underlying mechanisms are examined.
    IEEE Transactions on Nuclear Science 12/2012; 59(6):2785-2790. · 1.22 Impact Factor
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    ABSTRACT: a b s t r a c t Optimization of the probe adsorption has a major key in the preparation of electrochemical sensors for the detection of oligonucleotide sequences hybridization. The role of a mixed monolayer of ssDNA sequences and MCH coadsorbed on a gold electrode surface was studied in this work. The working elec-trode was modified by chemisorption using a solution of thiol-tethered 33-mer DNA probe and merca-ptohexanol (MCH), in a concentration range from 2 nM to 20 lM. The probe surface density was monitored by means of electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and chronocoulometry. From EIS measurements, the charge transfer resistance was obtained as a function of the MCH concentration in the immobilization solution. The time dependence of mixed SAM adsorption was also investigated. The SAM adsorption was characterized regarding the electrode surface coverage with DPV and EIS measurements. Moreover, the probe surface density was investigated with chronocoulometry in RuðNH 3 Þ 3þ 6 solution. Sensor behavior and sensitivity showed significant differ-ences as a function of ssDNA/MCH concentration ratio as hybridization detection efficiency decreases while increasing the MCH concentration. The effect of different probe density in the hybridization detec-tion efficiency was determined. Results demonstrated the effective of the coadsorption of ssDNA and thi-ols to control the SAM property and the probe density. It was therefore shown the importance to identify the correct density of probes on the electrode, below the saturation value, to ensure both a proper hybrid-ization process and having a high hybridization signal. Ó 2012 Elsevier B.V. All rights reserved.
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    ABSTRACT: We study the sensitivity to alpha particles of state-of-the-art Multi-Level Cell (MLC) and Single-Level Cell (SLC) NAND Floating Gate (FG) flash memories with NAND architecture. We show that starting from a feature size of 50 nm, MLC flash memories are sensitive to alpha particles, whereas SLC devices do not show any sensitivity down to a feature size of 34 nm. We calculate the alpha-induced soft error rates on the field, discuss technology trends in comparison to heavy-ions.
    Reliability Physics Symposium (IRPS), 2012 IEEE International; 01/2012
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    ABSTRACT: In this work we present the preliminary resulting measurements of an enzyme-based biosensor for the amperometric detection of lactic acid (LA). The sensor is based on low-cost gold electrodes on polymeric substrate. The redox catalytic enzyme used for analyte amperometric detection is lactate oxidase (LOx) from Pediococcus sp. This enzyme has been immobilized over electrodes surfaces by direct adsorption methodologies. Analysis of the enzyme-modified electrodes have been carried out by means of Electrochemical Impedance Spectroscopy (EIS) and with the development of an equivalent electrical model, in order to improve the adsorption process. Biosensors performance have been evaluated with Cyclic Voltammetry (CVM) measurements in different lactic acid solutions with concentrations from 1 μM up to 300 mM. The lactate sensitivity of this disposable biosensor results in about 6.24 μA mM-1 cm-2.
    International Conference on Biomedical Electronics and Devices; 01/2012
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    ABSTRACT: The paper describes power switching converters suitable for possible power supply distribution networks for the upgraded detectors at the High Luminosity LHC collider. The proposed topologies have been selected by considering their tolerance to the highly hostile environment where the converters will operate as well as their limited electromagnetic noise emission. The analysis focuses on the description of the power supplies for noble liquid calorimeters, such as the Atlas LAr calorimeters, though several outcomes of this research can be applied to other detectors of the future LHC experiments. Experimental results carried on demonstrators are provided.
    Journal of Instrumentation 01/2012; 7(03). · 1.66 Impact Factor
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    ABSTRACT: This work deals with the development of a disposable electrochemical biosensor for the specific detection of short DNA sequences. The sensor is an amperometric transducer with three planar electrodes, comprising a working, a counter and a pseudo-reference electrode, all made of a gold layer over a polycarbonate substrate. For the development of the genosensor, the working electrode was modified using thiol-tethered 33-mer DNA probe by chemisorptions, in a concentration range from 0.1 μM to 5 μM. Immobilization of ssDNA on gold surface was monitored with electrochem-ical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) in Fe(CN) 4−/3− 6 and Ruthenium(II)/(III) solutions. The time dependence of ssDNA probe immobilization was also studied. The hybridization detection is then compared with EIS and DPV measurements.
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    ABSTRACT: This paper reports the main contribution of a project devoted to the definition of techniques to design and evaluate fault tolerant systems implemented using the SoPC paradigm, suitable for missionand safety-critical application environments. In particular, the effort of the five involved research units has been devoted to address some of the main issues related to the specific technological aspects introduced by these flexible platforms. The overall target of the research is the development of a design methodology for highly reliable systems realized on reconfigurable platforms based on a System-on-Programmable Chip (SoPC), as discussed in the next section.
    Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT), 2012 IEEE International Symposium on; 01/2012
  • ISROS 2012; 01/2012
  • HETECH 2012; 01/2012
  • A.cester, A.paccagnella
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    ABSTRACT: We have briefly reviewed the most important degradation mechanisms affecting ultra-thin gate oxides after exposure to ionizing irradiation. The increase of the gate leakage current seems the most crucial issue for device lifetime, especially for non-volatile memory and dynamic logic. The build-up of positive charge in the oxide and the subsequent threshold voltage shift, which was the major concern for thicker oxide, are no longer appreciable in today's devices due to the reduced oxide thickness permitting a fast recombination of trapped holes with electrons from interfaces. Among the leakage currents affecting thin oxides we have considered here the Radiation Induced Leakage Current (RILC) and the Radiation Soft Breakdown (RSB). RILC is observed after irradiation with a low Linear Energy Transfer (LET) radiation source and comes from a trap-assisted tunneling of electrons mediated by the neutral traps produced by irradiation. RILC depends on the applied bias during irradiation and the maximum is measured when devices are biased in flat band. Contrarily to RILC, RSB is observed after irradiation with high LET ions and derives from the formation of several conductive paths across the oxide corresponding to the ion hits. RSB conduction is explained by the theory of the Quantum Point Contact as also proposed for the electrically induced Soft breakdown. Finally, we present some preliminary results, which indicate that although the direct effects of irradiation (in terms of gate leakage current increase) are small for oxide thinner than 3nm, it is possible that these devices may experience an accelerated wear-out and/or breakdown after subsequent electrical stress relative to a fresh (not irradiated) device.
    International Journal of High Speed Electronics and Systems 11/2011; 14(02).
  • S. Gerardin, A. Paccagnella
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    ABSTRACT: We discuss non-volatile memories (NVM) for space applications. The focus will be both on technologies and devices aimed at the mainstream commercial markets and on rad-hard devices. Commercial NVMs are very attractive for space designers due to their large size (tens of Gbits), even though they have several issues related to ionizing radiation. Rad-hard NVMs offer radiation hardness, but are available only in small size (few Mbits). Most of the emphasis in this review paper will be on the current dominant technology in the mainstream market: floating gate flash memories. A comprehensive discussion of total dose and single event effects results for a wide cross section of NVMs will be presented. Finally, we will conclude with a cursory glance at other emerging non-volatile technologies.
    IEEE Transactions on Nuclear Science 01/2011; · 1.22 Impact Factor
  • M. Bagatin, S. Gerardin, A. Paccagnella, F. Faccio
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    ABSTRACT: We analyzed the impact of negative bias temperature instability (NBTI) on the single-event upset rate of SRAM cells through experiments and SPICE simulations. We performed critical charge simulations introducing different degradation patterns in the cells, in three technology nodes, from 180 to 90 nm. The simulations results were checked with α-particle and heavy-ion irradiations on a 130-nm technology. Both simulations and experimental results show that NBTI degradation does not significantly affect the single-event upset SRAM cell rate as long as the parametric drift induced by aging is within 10%.
    IEEE Transactions on Nuclear Science 01/2011; · 1.22 Impact Factor

Publication Stats

2k Citations
276.43 Total Impact Points

Institutions

  • 1987–2014
    • University of Padova
      • Department of Information Engineering
      Padua, Veneto, Italy
  • 2010
    • California Institute of Technology
      • Jet Propulsion Laboratory
      Pasadena, CA, United States
  • 2002–2010
    • imec Belgium
      Louvain, Flanders, Belgium
    • University of Udine
      Udine, Friuli Venezia Giulia, Italy
  • 2005–2009
    • Autonomous University of Barcelona
      • Departamento de Ingeniería Electrónica
      Cerdanyola del Vallès, Catalonia, Spain
  • 2003–2005
    • Politecnico di Torino
      • DAUIN - Department of Control and Computer Engineering
      Torino, Piedmont, Italy
  • 2004
    • University of Buenos Aires
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2001
    • Università di Pisa
      Pisa, Tuscany, Italy
  • 1997
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 1994–1996
    • INFN - Istituto Nazionale di Fisica Nucleare
      Frascati, Latium, Italy
  • 1987–1988
    • Università degli Studi di Trento
      Trient, Trentino-Alto Adige, Italy