scholarly journals A CMOS-MEMS BEOL 2-axis Lorentz-Force Magnetometer with Device-Level Offset Cancellation

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5899
Author(s):  
Josep Maria Sánchez-Chiva ◽  
Juan Valle ◽  
Daniel Fernández ◽  
Jordi Madrenas
Keyword(s):  
Lorentz Force ◽  
Microelectromechanical Systems ◽  
Ambient Pressure ◽  
Complementary Metal Oxide Semiconductor ◽  
Consumer Electronics ◽  
Oxide Semiconductor ◽  
Mems Devices ◽  
Lateral Field ◽  
Offset Cancellation ◽  
Cmos Mems

Lorentz-force Microelectromechanical Systems (MEMS) magnetometers have been proposed as a replacement for magnetometers currently used in consumer electronics market. Being MEMS devices, they can be manufactured in the same die as accelerometers and gyroscopes, greatly reducing current solutions volume and costs. However, they still present low sensitivities and large offsets that hinder their performance. In this article, a 2-axis out-of-plane, lateral field sensing, CMOS-MEMS magnetometer designed using the Back-End-Of-Line (BEOL) metal and oxide layers of a standard CMOS (Complementary Metal–Oxide–Semiconductor) process is proposed. As a result, its integration in the same die area, side-by-side, not only with other MEMS devices, but with the readout electronics is possible. A shielding structure is proposed that cancels out the offset frequently reported in this kind of sensors. Full-wafer device characterization has been performed, which provides valuable information on device yield and performance. The proposed device has a minimum yield of 85.7% with a good uniformity of the resonance frequency fr¯=56.8 kHz, σfr=5.1 kHz and quality factor Q¯=7.3, σQ=1.6 at ambient pressure. Device sensitivity to magnetic field is 37.6fA·μT−1 at P=1130 Pa when driven with I=1mApp.

scholarly journals A Robust Fully-Integrated Digital-Output Inductive CMOS-MEMS Accelerometer with Improved Inductor Quality Factor

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 792
Author(s):  
Chiu ◽  
Liu ◽  
Hong
Keyword(s):  
Quality Factor ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Mems Devices ◽  
Digital Output ◽  
Detection Scheme ◽  
Mems Accelerometer ◽  
Analog To Digital Conversion ◽  
Cmos Mems ◽  
In Series

This paper presents the design, fabrication, and characterization of an inductive complementary metal oxide semiconductor micro-electromechanical systems (CMOS-MEMS) accelerometer with on-chip digital output based on LC oscillators. While most MEMS accelerometers employ capacitive detection schemes, the proposed inductive detection scheme is less susceptible to the stress-induced structural curling and deformation that are commonly seen in CMOS-MEMS devices. Oscillator-based frequency readout does not need analog to digital conversion and thus can simplify the overall system design. In this paper, a high-Q CMOS inductor was connected in series with the low-Q MEMS sensing inductor to improve its quality factor. Measurement results showed the proposed device had an offset frequency of 85.5 MHz, sensitivity of 41.6 kHz/g, noise floor of 8.2 mg/Hz, bias instability of 0.94 kHz (11 ppm) at an average time of 2.16 s, and nonlinearity of 1.5% full-scale.

Piezoelectric Thin Films for Sensors, Actuators, and Energy Harvesting

MRS Bulletin ◽  
2009 ◽  
Vol 34 (9) ◽  
pp. 658-664 ◽  
Author(s):  
P. Muralt ◽  
R. G. Polcawich ◽  
S. Trolier-McKinstry
Keyword(s):  
Thin Films ◽  
Energy Harvesting ◽  
Microelectromechanical Systems ◽  
Low Voltage ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Mems Devices ◽  
Si Substrates ◽  
The Impact

AbstractPiezoelectric microelectromechanical systems (MEMS) offer the opportunity for high-sensitivity sensors and large displacement, low-voltage actuators. In particular, recent advances in the deposition of perovskite thin films point to a generation of MEMS devices capable of large displacements at complementary metal oxide semiconductor-compatible voltage levels. Moreover, if the devices are mounted in mechanically noisy environments, they also can be used for energy harvesting. Key to all of these applications is the ability to obtain high piezoelectric coefficients and retain these coefficients throughout the microfabrication process. This article will review the impact of composition, orientation, and microstructure on the piezoelectric properties of perovskite thin films such as PbZr1−xTixO3 (PZT). Superior piezoelectric coefficients (e31, f of −18 C/m2) are achieved in {001}-oriented PbZr0.52Ti0.48O3 films with improved compositional homogeneity on Si substrates. The advent of such high piezoelectric responses in films opens up a wide variety of possible applications. A few examples of these, including low-voltage radio frequency MEMS switches and resonators, actuators for millimeter-scale robotics, droplet ejectors, energy scavengers for unattended sensors, and medical imaging transducers, will be discussed.

scholarly journals Portable Real-Time Detection of Pb(II) Using a CMOS MEMS-Based Nanomechanical Sensing Array Modified with PEDOT:PSS

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2454
Author(s):  
Yi-Kuang Yen ◽  
Chao-Yu Lai
Keyword(s):  
Limit Of Detection ◽  
Quality Measurement ◽  
Complementary Metal Oxide Semiconductor ◽  
Cost Effective ◽  
Sample Volume ◽  
Small Sample ◽  
Oxide Semiconductor ◽  
Resistance Change ◽  
Site Water ◽  
Cmos Mems

Detecting the concentration of Pb2+ ions is important for monitoring the quality of water due to it can become a health threat as being in certain level. In this study, we report a nanomechanical Pb2+ sensor by employing the complementary metal-oxide-semiconductor microelectromechanical system (CMOS MEMS)-based piezoresistive microcantilevers coated with PEDOT:PSS sensing layers. Upon reaction with Pb2+, the PEDOT:PSS layer was oxidized which induced the surface stress change resulted in a subsequent bending of the microcantilever with the signal response of relative resistance change. This sensing platform has the advantages of being mass-produced, miniaturized, and portable. The sensor exhibited its sensitivity to Pb2+ concentrations in a linear range of 0.01–1000 ppm, and the limit of detection was 5 ppb. Moreover, the sensor showed the specificity to Pb2+, required a small sample volume and was easy to operate. Therefore, the proposed analytical method described here may be a sensitive, cost-effective and portable sensing tool for on-site water quality measurement and pollution detection.

scholarly journals Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS–MEMS Technique

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 92 ◽  
Author(s):  
Wei-Chun Shen ◽  
Po-Jen Shih ◽  
Yao-Chuan Tsai ◽  
Cheng-Chih Hsu ◽  
Ching-Liang Dai
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
X Ray Diffraction ◽  
Ammonia Gas ◽  
Oxidation Reduction ◽  
Sensing Material ◽  
Voltage Signal ◽  
Cmos Mems ◽  
Good Repeatability

This study describes the fabrication of an ammonia gas sensor (AGS) using a complementary metal oxide semiconductor (CMOS)–microelectromechanical system (MEMS) technique. The structure of the AGS features interdigitated electrodes (IDEs) and a sensing material on a silicon substrate. The IDEs are the stacked aluminum layers that are made using the CMOS process. The sensing material; polypyrrole/reduced graphene oxide (PPy/RGO), is synthesized using the oxidation–reduction method; and the material is characterized using an electron spectroscope for chemical analysis (ESCA), a scanning electron microscope (SEM), and high-resolution X-ray diffraction (XRD). After the CMOS process; the AGS needs post-processing to etch an oxide layer and to deposit the sensing material. The resistance of the AGS changes when it is exposed to ammonia. A non-inverting amplifier circuit converts the resistance of the AGS into a voltage signal. The AGS operates at room temperature. Experiments show that the AGS response is 4.5% at a concentration of 1 ppm NH3; and it exhibits good repeatability. The lowest concentration that the AGS can detect is 0.1 ppm NH3

scholarly journals Active Thermoelectric Vacuum Sensor Based on Frequency Modulation

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 15 ◽  
Author(s):  
Shu-Jung Chen ◽  
Yung-Chuan Wu
Keyword(s):  
Frequency Modulation ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Harmonic Signal ◽  
Phase Lock Loop ◽  
Oxide Semiconductor ◽  
Alternative Approach ◽  
Vacuum Sensor ◽  
Cmos Mems ◽  
Mems Process

This paper introduces a thermoelectric-type sensor with a built-in heater as an alternative approach to the measurement of vacuum pressure based on frequency modulation. The proposed sensor is fabricated using the TSMC (Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan) 0.35 μm complementary metal-oxide-semiconductor-microelectro-mechanical systems (CMOS–MEMS) process with thermocouples positioned central-symmetrically. The proposed frequency modulation technique involves locking the sensor output signal at a given frequency using a phase-lock-loop (PLL) amplifier to increase the signal-to-noise ratio (SNR) and thereby enhance the sensitivity of vacuum measurements. An improved first harmonic signal detection based on asymmetrical applied heating gives a precise measurement. Following calibration, the output voltage is in good agreement with the calibration values, resulting in an error of 0.25% under pressures between 0.1–10 Torr.

Effects of etching holes on complementary metal oxide semiconductor–microelectromechanical systems capacitive structure

2012 ◽  
Vol 24 (3) ◽  
pp. 310-317 ◽  
Author(s):  
Wei-Hsiang Tu ◽  
Wen-Chang Chu ◽  
Chih-Kung Lee ◽  
Pei-Zen Chang ◽  
Yuh-Chung Hu
Keyword(s):  
Metal Oxide ◽  
Microelectromechanical Systems ◽  
Sacrificial Layer ◽  
Estimation Method ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Fringe Field ◽  
Large Area ◽  
Fringing Field

Etching the large area of sacrificial layer under the microstructure to be released is a common method used in microelectromechanical systems technology. In order to completely release the microstructures, many etching holes are often required on the microstructure to enable the etchant to completely etch the sacrificial layer. However, the etching holes often alter the electromechanical properties of the micro devices, especially capacitive devices, because the fringe fields induced by the etching holes can significantly alter the electrical properties. This article is aimed at evaluating the fringe field capacitance caused by etching holes on microstructures. The authors aim to find a general capacitance compensation formula for the fringe capacitance of etching holes by the use of ANSYS simulation. According to the simulation results, the design of a capacitive structure with small etching holes is recommended to prevent an extreme capacitance decrease. In conclusion, this article provides a fringing field capacitance estimation method that shows the capacitance compensation tendency of the design of etching holes; this method is expected to be applicable to the design in capacitive devices of complementary metal oxide semiconductor–microelectromechanical systems technology.

scholarly journals A highly stable, nanotube-enhanced, CMOS-MEMS thermal emitter for mid-IR gas sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Popa ◽  
Richard Hopper ◽  
Syed Zeeshan Ali ◽  
Matthew Thomas Cole ◽  
Ye Fan ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Low Cost ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Light Sources ◽  
Mir Spectroscopy ◽  
Sensing Applications ◽  
Cmos Mems ◽  
Extended Operation ◽  
On Chip

AbstractThe gas sensor market is growing fast, driven by many socioeconomic and industrial factors. Mid-infrared (MIR) gas sensors offer excellent performance for an increasing number of sensing applications in healthcare, smart homes, and the automotive sector. Having access to low-cost, miniaturized, energy efficient light sources is of critical importance for the monolithic integration of MIR sensors. Here, we present an on-chip broadband thermal MIR source fabricated by combining a complementary metal oxide semiconductor (CMOS) micro-hotplate with a dielectric-encapsulated carbon nanotube (CNT) blackbody layer. The micro-hotplate was used during fabrication as a micro-reactor to facilitate high temperature (>700 $$^{\circ }$$ ∘ C) growth of the CNT layer and also for post-growth thermal annealing. We demonstrate, for the first time, stable extended operation in air of devices with a dielectric-encapsulated CNT layer at heater temperatures above 600 $$^{\circ }$$ ∘ C. The demonstrated devices exhibit almost unitary emissivity across the entire MIR spectrum, offering an ideal solution for low-cost, highly-integrated MIR spectroscopy for the Internet of Things.

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