53 research outputs found
Compact and explicit physical model for lateral metal-oxide-semiconductor field-effect transistor with nanoelectromechanical system based resonant gate
We propose a simple analytical model of a metal-oxide-semiconductor
field-effect transistor with a lateral resonant gate based on the coupled
electromechanical equations, which are self-consistently solved in time. All
charge densities according to the mechanical oscillations are evaluated. The
only input parameters are the physical characteristics of the device. No extra
mathematical parameters are used to fit the experimental results. Theoretical
results are in good agreement with the experimental data in static and dynamic
operation. Our model is comprehensive and may be suitable for any
electromechanical device based on the field-effect transduction
Large-Scale Integration of Nanoelectromechanical Systems for Gas Sensing Applications
We have developed arrays of nanomechanical systems (NEMS) by large-scale integration, comprising thousands of individual nanoresonators with densities of up to 6 million NEMS per square centimeter. The individual NEMS devices are electrically coupled using a combined series-parallel configuration that is extremely robust with respect to lithographical defects and mechanical or electrostatic-discharge damage. Given the large number of connected nanoresonators, the arrays are able to handle extremely high input powers (>1 W per array, corresponding to <1 mW per nanoresonator) without excessive heating or deterioration of resonance response. We demonstrate the utility of integrated NEMS arrays as high-performance chemical vapor sensors, detecting a part-per-billion concentration of a chemical warfare simulant within only a 2 s exposure period
Neutral particle Mass Spectrometry with Nanomechanical Systems
Current approaches to Mass Spectrometry (MS) require ionization of the
analytes of interest. For high-mass species, the resulting charge state
distribution can be complex and difficult to interpret correctly. In this
article, using a setup comprising both conventional time-of-flight MS (TOF-MS)
and Nano-Electro-Mechanical-Systems-based MS (NEMS-MS) in situ, we show
directly that NEMS-MS analysis is insensitive to charge state: the spectrum
consists of a single peak whatever the species charge state, making it
significantly clearer than existing MS analysis. In subsequent tests, all
charged particles are electrostatically removed from the beam, and unlike
TOF-MS, NEMS-MS can still measure masses. This demonstrates the possibility to
measure mass spectra for neutral particles. Thus, it is possible to envisage
MS-based studies of analytes that are incompatible with current ionization
techniques and the way is now open for the development of cutting edge system
architectures with unique analytical capability
High Frequency top-down Junction-less Silicon Nanowire Resonators
We report here the first realization of top-down silicon nanowires (SiNW)
transduced by both junction-less field effect transistor (FET) and the
piezoresistive (PZR) effect. The suspended SiNWs are among the smallest
top-down SiNWs reported to date, featuring widths down to ~20nm. This has been
achieved thanks to a 200mm-wafer-scale, VLSI process fully amenable to
monolithic CMOS co-integration. Thanks to the very small dimensions, the
conductance of the silicon nanowire can be controlled by a nearby electrostatic
gate. Both the junction-less FET and the previously demonstrated PZR
transduction have been performed with the same SiNW. These self-transducing
schemes have shown similar signal-to-background ratios, and the PZR
transduction has exhibited a relatively higher output signal. Allan deviation
AD of the same SiNW has been measured with both schemes, and we obtain AD~20ppm
for the FET detection and AD~3ppm for the PZR detection at room temperature and
low pressure. Orders of magnitude improvements are expected from tighter
electrostatic control via changes in geometry and doping level, as well as from
CMOS integration. The compact, simple topology of these elementary SiNW
resonators opens up new paths towards ultra-dense arrays for gas and mass
sensing, time keeping or logic switching systems in SiNW-CMOS platform
Nano Electro Mechanical Devices for Physical and Chemical Sensing
The emergence of MEMS in consumer applications has dramatically increased market perspectives but also puts very strong constraints on cost and integration issues. Addressing these issues through further size reduction is not always relevant as it does not allow maintaining a correct signal to noise ratio (SNR) for the ubiquitous capacitive MEMS sensors. Different solutions are presented here according to the nature of the signal to be sensed: For physical sensors a new concept mixing a micron sized proof mass and a nano-sized detection structure is described. For chemical sensors, the reduction in size actually presents some advantages in terms of high resonant frequency, reduced gas damping, and high sensitivity to applied forces or added mass. Application of nano-resonators to gaz sensing is depicted. Developed originally at the end of the 80's, Micro Electro Mechanical Systems (MEMS) have by now given rise to a mature industry generating this year almost a 10 billion US$ turnover: Silicon micromachining techniques made possible the realisation of ultra-miniature and low cost sensors that allowed the deployment of airbags in cars (MEMS accelerometers are used there to measure the deceleration related to an accident), and more recently, new functions in smart phones. This deployment in large volume applications has triggered interest from large semiconductor industries (STM, TI, Freescale…) and a strong competition towards lower cost and higher integration: The new Grail of the industry is the realization of a 9 Degrees of Freedom sensor, combining the measurement in the 3 directions of space of acceleration, rotation speed and earth magnetic field. As inspired by the semiconductor industry, an obvious answer to these needs is to further decrease the size of the sensors, from Micro to Nano Electro Mechanical Systems (NEMS). However, even taking apart the technological challenges, this is not that simple as physics laws are not always in favour of scaling down: A simple homothetic size reduction does not allow maintaining a correct signal to noise ratio (SNR). As it will be seen here, different types of sensors require different approaches. Nano size detection for physical sensors. As mentioned before, inertial sensors are becoming one of the most ubiquitous sensor today, with applications in industrial, automotive or consumer applications. Further miniaturization is highly sought, as it allows both to decrease the cost (proportional to the surface of silicon) and increase integration (mandatory in portable applications such as smartphones, tablets…). However simple reduction of the seismic mass affects the sensitivity and reduces the nominal capacitance (95% of commercial MEM
Self-oscillation conditions of a resonant-nano-electromechanical mass sensor
International audienceThis article presents a comprehensive study and design methodology of co-integrated oscillators for nano mass sensing application based on resonant Nano-Electro-Mechanical-System (NEMS). In particular, it reports the capacitive with the piezoresistive transduction schemes in terms of the overall sensor performance. The developed model is clearly in accordance with the general experimental observations obtained for NEMS-based mass detection. The piezoresistive devices are much sensitive (up to 10 zg/√Hz) than capacitive ones (close to 100 zg/√Hz) since they can work at higher frequency. Moreover, the high doped silicon piezoresistive gauge, which is of a great interest for very large scale integration displays similar theoretical resolution than the metallic gauge already used experimentally
Single-protein nanomechanical mass spectrometry in real time
Nanoelectromechanical systems (NEMS) resonators can detect mass with exceptional sensitivity. Previously, mass spectra from several hundred adsorption events were assembled in NEMS-based mass spectrometry using statistical analysis. Here, we report the first realization of single-molecule NEMS-based mass spectrometry in real time. As each molecule in the sample adsorbs on the resonator, its mass and position of adsorption are determined by continuously tracking two driven vibrational modes of the device. We demonstrate the potential of multimode NEMS-based mass spectrometry by analysing IgM antibody complexes in real time. NEMS-based mass spectrometry is a unique and promising new form of mass spectrometry: it can resolve neutral species, provide a resolving power that increases markedly for very large masses, and allow the acquisition of spectra, molecule-by-molecule, in real time
Quantum entanglement with acousto-optic modulators: 2-photon beatings and Bell experiments with moving beamsplitters
We present an experiment testing quantum correlations with frequency shifted
photons. We test Bell inequality with 2-photon interferometry where we replace
the beamsplitters by acousto-optic modulators, which are equivalent to moving
beamsplitters. We measure the 2-photon beatings induced by the frequency
shifts, and we propose a cryptographic scheme in relation. Finally, setting the
experiment in a relativistic configuration, we demonstrate that the quantum
correlations are not only independent of the distance but also of the time
ordering between the two single-photon measurements.Comment: 14 pages, 16 figure
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