A 3-D micromechanical multi-loop magnetometer driven off-resonance by an on-chip resonator

This paper presents the principle and complete characterization of a single-chip unit formed by microelectromechanical system magnetometers to sense the 3-D magnetic field vector and a Tang resonator. The three sensors, nominally with the same resonance frequency, are operated 200-Hz off-resonance through an ac current whose reference frequency is provided by the resonator embedded in an oscillating circuit. The sensors gain is increased by adopting a current recirculation strategy using metal strips directly deposited on the structural polysilicon. At a driving value of 100 μArms flowing in series through the three devices, the magnetometers show a sub-185 nT/Hz Hz resolution with a selectable bandwidth up to 50 Hz. Over a ±5-mT full-scale range, the sensitivity curves show linearity errors lower than 0.2%, with high cross-axis rejection and immunity to external accelerations. Under temperature changes, the stability of the 200-Hz difference between the magnetometers and the resonator frequency is within 55 ppm/K. Offset is trimmed down to the microtesla range, with an overall measured Allan stability of about 100 nT at 20-s observation time. [2016-0030

Nanotechnology in Medicine: From Inception to Market Domination

Born from the marriage of nanotechnology and medicine, nanomedicine is set to bring advantages in the fight against unmet diseases. The field is recognized as a global challenge, and countless worldwide research and business initiatives are in place to obtain a significant market position. However, nanomedicine belongs to those emerging sectors in which business development methods have not been established yet. Open issues include which type of business model best fits these companies and which strategies would lead them to sustained growth. This paper describes the financial and strategic decisions by nanomedicine start-ups to reach the market successfully, obtain a satisfactory market share, and build and maintain a competitive defendable advantage. Walking nanomedicine-product from the hands of the inventor to those of the doctor, we explored the technological transfer process, which connects laboratories or research institutions to the marketplace. The process involves detailed analysis to evaluate the potentials of end-products, and researches to identify market segment, size, structure, and competitors, to ponder a possible market entry and the market share that managers can realistically achieve at different time horizons. Attracting funds is crucial but challenging. However, investors are starting to visualize the potentials of this field, magnetized by the business of “nano.

Solving FSR Versus Offset-Drift Trade-Offs with Three-Axis Time-Switched FM MEMS Accelerometer

This paper describes the working principle, the design, and the characterization of a three-axis frequency-modulated MEMS accelerometer, in which the differential frequency readout is performed through a novel time-switched approach. The proposed methodology is based on a double sampling of the oscillation frequency of a single resonator, consecutively biased in two different configurations in time. This technique enables to avoid offset thermal drift contributions typical of differential resonant accelerometers based on two distinct resonators with unavoidable mismatch in the temperature coefficient of frequency (TCf). Alternatively, a residual TCf offset drift component can be tuned to counterbalance other drift sources (e.g., stress-related), allowing a complete cancellation of the zero-g-offset (ZGO) thermal drift. Experiments on various samples report repeatable sub- 50μ g/K thermal drift without post-acquisition corrections, with a full-scale higher than 32g at a 100μ g/√ Hz consumer-grade resolution. [2018-0089]

Modelling and testing of a MEMS accelerometer controlled and read-out beyond the pull-in instability limit

Abstract Electrostatic forces caused by the readout circuit and parasitic capacitances have much relevance in the scaling considerations of Micro and Nano electro mechanical (M/NEMS) parallel-plate motion sensors. The reduction of minimum geometrical dimensions (spring width, air gap), aimed at an improvement of the sensitivity/area ratio, is indeed limited by the pull-in instability determined by the electrostatic attraction between parallel plates. In this paper it is presented a compact MEMS accelerometer built in the ST Microelectronics ThELMA technology, together with a 0.35μm CMOS switched-capacitor circuit, suitably designed to avoid the pull-in. In particular we focus on the model of the MEMS, written in a Hardware Description Language file to be used directly in the VLSI circuit simulator. Although the MEMS is unstable at the chosen biasing conditions when read-out at fixed voltage, the experimental results show that the closed-loop circuit allows the biasing beyond the pull-in voltage, in good agreement with the simulation prediction. The sensing range is larger than ±9 g with a resolution of 2 mg / Hz