This paper reports on ultra-scaled single-crystal Si NEMS resonators (25-40 nm thick) operating in the 10-100 MHz frequency range. Their first monolithic integration at the front-end level with CMOS enables to extract the signal from background leading to possible implementation of direct/homodyne measurement, for high sensitivity sensing applications and portable systems.

This article proposes a silicon-on-insulator complementary metal-oxide semiconductor (CMOS) micro-electromechanical system (MEMS) thin-film pressure sensor in which the sensing elements are based on stress-sensitive MOSFETs, and the carrier mobility and channel resistance vary with applied pressure. Four MOSFETs are embedded within a silicon dioxide membrane to form a Wheatstone bridge. The sensors are fabricated in a commercial foundry with p-channel and n-channel designs both investigated. The fabricated pMOSFET design gave a pressure sensitivity of 5.21 mV/kPa, whereas the nMOSFET gave about half the sensitivity at 2.40 mV/kPa. This shows a highly sensitive pressure sensor, with improved sensitivity on traditional piezoresistors, as well as significantly higher sensitivity than current MOSFET based pressure sensors. Moreover, the maximum dc power consumption was only 190 and 390 μW for the pMOSFET and nMOSFET, respectively. This low-cost, low-power, high-sensitivity CMOS MEMS technology with on-chip electronics could be used toward the implementation of MOSFET-based pressure transduction in a multitude of industrial and other applications.

We report on the first experimental demonstration of a self-oscillator based on a single-crystal silicon NEMS resonator monolithically co-integrated with a CMOS circuitry. The latter, composed only by seven transistors, is manufactured with a very low-cost 0.35μm technology. The NEMS-CMOS self-oscillator pixel is as small as 50×70 μm ² (pads excluded) and can oscillate near 8MHz. In this paper are described the NEMS-CMOS oscillator characteristics and the implementation method of the self-oscillating loop.

This paper reports the indoor wireless measurement of pressure from zero-power (or passive) microwave (24 GHz) sensors. The sensors are packaged and allow the remote measurement of overpressure up to 2.1 bars. Their design, fabrication process and packaging are detailed. From the measurement of sensor scattering parameters, the outstanding sensitivity of 995 MHz/bar between 0.8 and 2.1 bars was achieved with the full-scale measurement range of 1.33 GHz. Moreover, the 3D radar imagery technique was applied for the remote interrogation of these sensors in electromagnetic reverberant environments. The full-scale dynamic range of 4.9 dB and the sensitivity of 4.9 dB/bar between 0.7 and 1.7 bars were achieved with radar detection in a highly reflective environment. These measurement results demonstrate for the first time the ability of the radar imagery technique to interrogate fully passive pressure sensors in electromagnetic reverberant environments.

This article describes the wireless and simultaneous interrogation and identification of multiple passive (zero-power) pressure sensors in an industrial environment with a reading range of at least 4 m. The 3-D beamscanning of the scene is performed from a 24-GHz frequency-modulated continuous-wave (FM-CW) radar and for diverse electric field polarizations. The identification is performed using a k-nearest neighbor classification. The benefit of using the cross-polarized electric fields combined with a radar imagery technique is enlightened from the analysis of the background clutter and the simultaneous remote interrogation of several passive pressure sensors at a distance up to 17.7 m. The measurement uncertainty on pressure obtained from the proposed long-range wireless technique is finally reported and discussed.