Comprehensive characterization results of CMOS-microelectromechanical systems resonant pressure sensor are presented. We have extensively evaluated the key performance parameters of our device in terms of quality factor (Q) variations under variable conditions of temperature and pressure, characterized by Knudsen number (K _n ). The fundamental frequency of the reported device is 104.3 kHz. Over the full-scale pressure range of 0.1 to 100 kPa and a temperature range of -10 °C to 85 °C, Q from 450 to 62.6 have been obtained. Besides, static variations of the device capacitance have been measured and analyzed with temperature to evaluate the spring softening and the pull-in effects. A nonlinearity analysis has been performed to assess the device stability. Furthermore, a statistical mismatch analysis has been carried out to determine the deviation of resonance with etching time and ascertain maximum device yield. With our in-house back-end of line metal-layer release, this sensor can be monolithically embedded in the same substrate as standard CMOS integrated circuits, resulting in a significant cost and area reduction.

This paper presents a behavioral modeling technique for CMOS-MEMS microresonators that enables simulation of a MEMS resonator model in Analog Hardware Description Language (AHDL) format within a system-level circuit simulation. A 100 kHz CMOS-MEMS resonant pressure sensor has been modeled into Verilog-A code and successfully simulated within Cadence framework. Analysis has shown that simulation results of the reported model are in agreement with the device characterization results. As an application of the proposed methodology, simulation and results of the model together with an integrated monolithic low-noise amplifier is exemplified for detecting the position change of the resonator.

Wireless implantable devices have revolutionized the field of biomedical engineering for as long as adequate power supplies are conjured. This paper presents an ultrasonic power link front-end interfaced with a capacitive micromachined ultrasonic transducer (CMUT). The ultrasonic power link front-end consists of a rectifier, a charge pump, a clock extractor and a phase generator. The power link front-end designed in 0.18-μm CMOS process provides a 17 V DC supply for the implant microsystem, e.g. neural stimulator. It achieves an overall power efficiency of 0.3% in simulation.

This work presents the design and characterization of a resonant CMOS-MEMS pressure sensor manufactured in a standard 180 nm CMOS industry-compatible technology. The device consists of aluminum square plates attached together by means of tungsten vias integrated into the back end of line (BEOL) of the CMOS process. Three prototypes were designed and the structural characteristics were varied, particularly mass and thickness, which are directly related to the resonance frequency, quality factor, and pressure; while the same geometry at the frontal level, as well as the air gap, were maintained to allow structural comparative analysis of the structures. The devices were released through an isotropic wet etching step performed in-house after the CMOS die manufacturing, and characterized in terms of Q-factor vs. pressure, resonant frequency, and drift vs. temperature and biasing voltage.

In this paper, we present a study of the quality factor (Q) behavior of a CMOS-MEMS resonator under different conditions of temperature and pressure. The device has been manufactured using standard 250 nm CMOS technology followed by an in-house BEOL metal-layer release wet etching. The manufactured sensor is used as a pressure estimator based on the variation of Q. Experiments have demonstrated an inverse relationship between the resonator Q and temperature in different pressure regimes. The initial Q has decreased to 0.80*Q at 100 Pa when the temperature changed from 300 K to 360 K, and to 0.65*Q at atmospheric pressure under the same temperature span. The static capacitance variations of the device with temperature have also been measured.