Eric Colinet

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 upon the NEMS resonator, its mass and the 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 analyzing IgM antibody complexes in real-time. NEMS-MS is a unique and promising new form of mass spectrometry: it can resolve neutral species, provides resolving power that increases markedly for very large masses, and allows acquisition of spectra, molecule-by-molecule, in real-time.

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.

Frequency fluctuations in silicon nanoresonators

Frequency stability is key to performance of nanoresonators. This stability is thought to reach a limit with the resonator’s ability to resolve thermally-induced vibrations. Although measurements and predictions of resonator stability usually disregard fluctuations in the mechanical frequency response, these fluctuations have recently attracted considerable theoretical interest. However, their existence is very difficult to demonstrate experimentally. Here, through a literature review, we show that all studies of frequency stability report values several orders of magnitude larger than the limit imposed by thermomechanical noise. We studied a monocrystalline silicon nanoresonator at room temperature, and found a similar discrepancy. We propose a new method to show this was due to the presence of frequency fluctuations, of unexpected level. The fluctuations were not due to the instrumentation system, or to any other of the known sources investigated. These results challenge our current understanding of frequency fluctuations and call for a change in practices.

Ultra-Sensitive Capacitive Detection Based on SGMOSFET Compatible With Front-End CMOS Process

Capacitive measurement of very small displacement of nano-electro-mechanical systems (NEMS) presents some issues that are discussed in this article. It is shown that performance is fairly improved when integrating on a same die the NEMS and CMOS electronics. As an initial step toward full integration, an in-plane suspended gate MOSFET (SGMOSFET) compatible with a front-end CMOS has been developed. The device model, its fabrication, and its experimental measurement are presented. Performance obtained with this device is experimentally compared to the one obtained with a stand-alone NEMS readout circuit, which is used as a reference detection system. The 130 nm CMOS ASIC uses a bridge measurement technique and a high sensitive first stage to minimize the influence of any parasitic capacitances.

Self-oscillation conditions of a resonant nanoelectromechanical mass sensor

This article presents a comprehensive study and design methodology of cointegrated oscillators for nanoscale mass sensing applications based on resonant nanoelectromechanical system (NEMS). In particular, a comparison is provided between the capacitive and the piezoresistive transduction schemes in terms of 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 more sensitive (up to 10u2002zg/√Hz) than capacitive ones (close to 100u2002zg/√Hz) since they can work at higher frequency. Moreover, the high doped silicon piezoresistive gauge, which is of great interest for very large scale integration, shows similar theoretical resolution to that of the metallic gauge already used experimentally.

H∞ Loop shaping control for PLL-based mechanical resonance tracking in NEMS resonant mass sensors

A simple dynamic detection of the resonance frequency shift in NEMS resonant mass sensors is described. This is done without the use of an external frequency sweep signal nor a frequency counter limiting the dynamic variation detection. Neither an amplitude control nor a phase switcher is required for maintaining the resonant oscillations. The sensor is driven directly by the VCOpsilas output for which the control signal is calculated by a robust Hinfin controller using loop-shaping method. Only the sensor and the VCOpsilas signals signs are detected and compared so that the controller regulates the phase difference between them, maintaining it at pi/2 which occurs on resonance frequency. The measurement issue is transformed to a novel control problem that rejects the disturbance described by the resonance frequency shift, attenuates the phase noise and guarantees good stability margins.

Measurement of Nano-Displacement Based on In-Plane Suspended-Gate MOSFET Detection Compatible with a Front-End CMOS Process

The first front-end CMOS co-integration based on the lateral SGMOSFET presented in this paper demonstrates the benefit of a co-integration approach for NEMS devices. Performance using this device is compared to that obtained with a standalone ASIC. The next step will consist of replacing equivalently the input transistor of the ASIC cascode structure by the SGMOSFET.

Modal control of mechanically coupled NEMS arrays for tunable RF filters

A novel tuning strategy of nanoelectromechanical systems (NEMS)-based filters is proposed based on the modal control of mechanically coupled NEMS arrays. This is done by adjusting separately addressed distributed actuation and detection configurations proportionally to desired modal vectors. This control scheme enhances the global output signal, raising the power handling of the filter on all channels. Although the modal control of 1-D arrays exhibits narrow-band responses with adjustable resonance frequency, its application to 2-D arrays produces filters with both adjustable bandwidth and central frequency. One possible realization scheme is suggested by using electrostatically driven coupled NEMS arrays whose transduction gains are adjusted by changing the electrodes bias voltages. Dispersion effects on both 1-D array and 2-D array frequency response are analytically expressed using eigenvalues perturbation theory. Based on these results, we show how to reduce their impact by appropriately choosing the coupling stiffness and the number of resonators.

A 100Hz 5nT/Hz Low-Pass /spl Delta//spl Sigma/ Servo-Controlled Microfluxgate Magnetometer Using Pulsed Excitation

An ASIC for an integrated microfluxgate sensor uses pulsed excitation, a 2nd-order DeltaSigma modulator, an LPF and an FIR DAC current generator in a fully-digital field-canceling loop to achieve high linearity over a 120muT DR. A low noise floor of 5nTA/radicHz is measured over a 100Hz BW. This ASIC can be adapted to numerous applications since it is fully programmable. The 9mm2 ASIC consumes 36mW from 3.3V and is fabricated in a 0.35mum CMOS process.

A robust control method for electrostatic microbeam dynamic shaping with capacitive detection

A robust closed-loop control and observation methodology for a microbeam electrostatic dynamic shaping using N small separate electrodes is described. After decomposing the displacements vector on the n eigenmodes using the modal analysis, n controllers are designed to control the dynamic coefficients of each mode and deliver the stresses that must be distributed throughout the beam. In a previous work, we considered direct access to non noisy displacement measurements. In this paper, we investigate the capacitive measurement of the local displacements done by each small electrode, which gives a noisy readout. Robust control methodology applied on extended standard model allows the design of n observers associated to n controllers and guarantees a precise shape tracking, free from noise and robust against parameters incertitude.