7,346 research outputs found

    SEU sensitivity and modeling using picosecond pulsed laser stimulation of a D Flip-Flop in 40 nm CMOS technology

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    International audience—This paper presents the design of a CMOS 40 nm D Flip-Flop cell and reports the laser fault sensitivity mapping both with experiments and simulation results. Theses studies are driven by the need to propose a simulation methodology based on laser/silicon interactions with a complex integrated circuit. In the security field, it is therefore mandatory to understand the behavior of sensitive devices like D Flip-Flops to laser stimulation. In previous works, Roscian et al., Sarafianos et al., Lacruche et al. or Courbon et al. studied the relations between the layout of cells, its different laser-sensitive areas and their associated fault model using laser pulse duration in the nanosecond range. In this paper, we report similar experiments carried out using a shorter laser pulse duration (30 ps instead of 50 ns). We also propose an upgrade of the simulation model they used to take into account laser pulse durations in the picosecond range on a logic gate composed of a large number of transistors for a recent CMOS technology (40 nm)

    Electro-optic network analyzer

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    The bandwidth of frequency domain measurement methods of electrical signals has usually been far greater than the bandwidth of time domain methods. The primary limits of the time domain approach have been the 20 to 30 GHz bandwidth limit for electronic waveform acquisition instrumentation, and the lack of usable electrical pulse generators for excitation of a test device. The bandwidth of frequency domain network analysis appears to have reached a plateau of between 100 to 200 GHz, while time domain measurement have improved markedly in both bandwidth and sensitivity with the introduction of the pulsed laser based electro-optic sampling approach. Network analysis or the measurement of device scattering parameters provides information necessary to the design of electronic network such as high frequency amplifiers, mixers, and phase shifter. The bandwidth of frequency domain network analysis is currently being exceeded by the next generations of high frequency transistors and devices. Thus the electro-optic approach is a natural means of extending network analysis into the range above 100 GHz by employing time domain methods. In this approach, a suitable electrical excitation pulse is generated and propagated along a transmission line toward a test device. In the picosecond domain, laser driven photoconductive switches provide a unique method of generating electrical transients. Several materials were studied for generating short electrical pulses using photoconductive switches. The various semiconductive materials tested for photoconductive switching, and the electro-optic measurement technique used to characterize the material performance are described

    Mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum-well configurations

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    A microscopic study of mode-locked pulse generation is presented for vertical external-cavity surface-emitting lasers utilizing type-II quantum well configurations. The coupled Maxwell semiconductor Bloch equations are solved numerically where the type-II carrier replenishment is modeled via suitably chosen reservoirs. Conditions for stable mode-locked pulses are identified allowing for pulses in the \unit[100]{fs} range. Design strategies for type-II configurations are proposed that avoid potentially unstable pulse dynamics.Comment: Main paper with supplementary material

    Laser Fault Injection into SRAM cells: Picosecond versus Nanosecond pulses

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    International audience—Laser fault injection into SRAM cells is a widely used technique to perform fault attacks. In previous works, Roscian and Sarafianos studied the relations between the layout of the cell, its different laser-sensitive areas and their associated fault model using 50 ns duration laser pulses. In this paper, we report similar experiments carried out using shorter laser pulses (30 ps duration instead of 50 ns). Laser-sensitive areas that did not appear at 50 ns were observed. Additionally, these experiments confirmed the validity of the bit-set/bit-reset fault model over the bit-flip one. We also propose an upgrade of the simulation model they used to take into account laser pulses in the picosecond range. Finally, we performed additional laser fault injection experiments on the RAM memory of a microcontroller to validate the previous results

    Laminated chemical and physical micro-jet actuators based on conductive media

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    This dissertation presents the development of electrically-powered, lamination-based microactuators for the realization of large arrays of high impulse and short duration micro-jets with potential applications in the field of micro-electro-mechanical systems (MEMS). Microactuators offer unique control opportunities by converting the input electrical or chemical energy stored in a propellant into useful mechanical energy. This small and precise control obtained can potentially be applied towards aerodynamic control and transdermal drug delivery applications. This thesis discusses the development of both chemical and physical microactuators and characterizes their performance with focus towards the feasibility of using them for a specific application. The development of electrically powered microactuators starts by fabricating an array of radially firing microactuators using lamination-based micro fabrication techniques that potentially enable batch fabrication at low cost. The microactuators developed in this thesis consist of three main parts: a micro chamber in which the propellant is stored; two electrode structures through which electrical energy is supplied to the propellant; and a micro nozzle through which the propellant or released gases from the propellant are expanded as a jet. The fabricated actuators are then integrated with MEMS-process-compatible propellants and optimized to produce rapid ignition of the propellant and generate a fluidic jet. This rapid ignition is achieved either by making the propellant itself conductive, thus, passing an electric current directly through the propellant; or by discharging an arc across the propellant by placing it between two closely spaced electrodes. The first concept is demonstrated with chemical microactuators for the application of projectile maneuvering and the second concept is demonstrated with physical microactuators for transdermal drug delivery application. For both the actuators, the propellant integrated microactuators are characterized for performance in terms of impulse delivered, thrust generated and duration of the jet. The experimentally achieved results are validated by comparing with results from theoretical modeling. Finally, the feasibility of using chemical microactuators for maneuvering the path of a 25 mm projectile spinning at 500 Hz is discussed and the feasibility of applying the physical microactuators for increasing skin's permeability to drug analog molecules is studied.Ph.D.Committee Chair: Allen, Mark; Committee Member: Allen, Sue; Committee Member: Glezer, Ari; Committee Member: Koros, Williams; Committee Member: Prausnitz, Mar

    Preferential Electrical Stimulation of Small Nociceptive Fibers and Induction of Secondary Hyperalgesia

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    Development and testing of a solid core fiber optic delivery system and ultraviolet preionization for laser ignition

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    2012 Summer.Includes bibliographical references.Laser ignition of natural gas engines has shown potential to improve many facets of engine performance including brake thermal efficiency, exhaust emissions, and durability as compared with traditional spark ignition. Laser ignition technology has yet to transition to industry primarily because no system for reliably and safely delivering the laser pulse to the combustion chamber exists. This thesis presents a novel fiber optic delivery approach using solid core multimode step index silica fibers with large cladding diameters (400 ÎĽm core, 720 ÎĽm cladding). Testing was done on the fibers to determine their response to bending, vibration, high power input, and long duration beam transmission. It was found that in configurations representative of what is required on a real engine, and in the presence of vibration, reliable spark formation could be achieved in pressures as low as 3.4 bar using a specially designed optical spark plug. Comparative tests between the fiber delivered laser ignition system and a traditional J-gap spark plug were performed on a single cylinder Waukesha Cooperative Fuel Research (CFR) engine running on bottled methane. Tests were run at three different Net Mean Effective Pressures (NMEP) of 6, 8, and 12 bar at various air-fuel ratios. Results indicate reliable performance of the fiber and improved engine performance at high NMEP and lean conditions. Thesis research also includes initial studies into the use of dual laser pulses for plasma formation and ignition. In this approach, a first ultraviolet pulse preionizes a volume of air while a second overlapped pulse adds additional energy. Electron density measurements reveal the ultraviolet beam generates substantial preionization even with no visual breakdown, and Schlieren images are used to study the interaction between the two beams at atmospheric and lower pressures

    Designing a VMI Spectrometer Lens for Mid Infrared Strong-Field and Attosecond XUV Photoionization Experiments

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    A velocity map imaging spectrometer has been designed for experiments involving strong field and linear ionization of atoms using ultrashort laser pulses. The spectrometer will be used to replace conventional time-of-flight measuring devices for measuring the energy distribution of electrons released after ionization. A high energy resolution electrostatic lens design has been modeled for resolving photoelectron energies up to 400 eV and another design has been modeled for resolving photoelectrons up to 1 keV, which are a product ionization experiments involving intense, 3.6 ÎĽm wavelength laser pulses. The spectrometer is designed to be customizable, allowing for different lens designs and configurations for each experiment it is used for. The total project has been ongoing for approximately 1 year and will likely continue for another 4-6 months after the completion of this thesis.The National Science FoundationNo embarg

    Mitigating radiation damage of single photon detectors for space applications

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    Single-photon detectors in space must retain useful performance characteristics despite being bombarded with sub-atomic particles. Mitigating the effects of this space radiation is vital to enabling new space applications which require high-fidelity single-photon detection. To this end, we conducted proton radiation tests of various models of avalanche photodiodes (APDs) and one model of photomultiplier tube potentially suitable for satellite-based quantum communications. The samples were irradiated with 106 MeV protons at doses approximately equivalent to lifetimes of 0.6 , 6, 12 and 24 months in a low-Earth polar orbit. Although most detection properties were preserved, including efficiency, timing jitter and afterpulsing probability, all APD samples demonstrated significant increases in dark count rate (DCR) due to radiation-induced damage, many orders of magnitude higher than the 200 counts per second (cps) required for ground-to-satellite quantum communications. We then successfully demonstrated the mitigation of this DCR degradation through the use of deep cooling, to as low as -86 degrees C. This achieved DCR below the required 200 cps over the 24 months orbit duration. DCR was further reduced by thermal annealing at temperatures of +50 to +100 degrees C.Comment: The license has been corrected. Note that the license of v2 was incorrect and not valid. No other changes since v
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