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.

scholarly journals Implementation of a CMOS/MEMS Accelerometer with ASIC Processes

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 50 ◽  
Author(s):  
Yu-Sian Liu ◽  
Kuei-Ann Wen
Keyword(s):  
Integrated Circuit ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Mems Accelerometer ◽  
Cmos Mems ◽  
Application Specific Integrated Circuit ◽  
Micro Electromechanical System ◽  
Application Specific ◽  
Mems Process

This paper presents the design, simulation and mechanical characterization of a newly proposed complementary metal-oxide semiconductor (CMOS)/micro-electromechanical system (MEMS) accelerometer. The monolithic CMOS/MEMS accelerometer was fabricated using the 0.18 μm application-specific integrated circuit (ASIC)-compatible CMOS/MEMS process. An approximate analytical model for the spring design is presented. The experiments showed that the resonant frequency of the proposed tri-axis accelerometer was around 5.35 kHz for out-plane vibration. The tri-axis accelerometer had an area of 1096 μm × 1256 μm.

scholarly journals Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3610
Author(s):  
Adrián J. Torregrosa ◽  
Emir Karamehmedović ◽  
Haroldo Maestre ◽  
María Luisa Rico ◽  
Juan Capmany
Keyword(s):  
Optical Communications ◽  
Near Infrared ◽  
Nonlinear Crystal ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Infrared Image ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Oxide Semiconductor ◽  
Free Space Optical

Up-conversion sensing based on optical heterodyning of an IR (infrared) image with a local oscillator laser wave in a nonlinear optical sum-frequency mixing (SFM) process is a practical solution to circumvent some limitations of IR image sensors in terms of signal-to-noise ratio, speed, resolution, or cooling needs in some demanding applications. In this way, the spectral content of an IR image can become spectrally shifted to the visible/near infrared (VIS/NWIR) and then detected with silicon focal plane arrayed sensors (Si-FPA), such as CCD/CMOS (charge-coupled and complementary metal-oxide-semiconductor devices). This work is an extension of a previous study where we recently introduced this technique in the context of optical communications, in particular in FSOC (free-space optical communications). Herein, we present an image up-conversion system based on a 1064 nm Nd3+: YVO4 solid-state laser with a KTP (potassium titanyl phosphate) nonlinear crystal located intra-cavity where a laser beam at 1550 nm 2D spatially-modulated with a binary Quick Response (QR) code is mixed, giving an up-converted code image at 631 nm that is detected with an Si-based camera. The underlying technology allows for the extension of other IR spectral allocations, construction of compact receivers at low cost, and provides a natural way for increased protection against eavesdropping.

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.

Research on a New Metal-N-Poly Thermoelectric Material Sensor for Vacuum Sensing with Self Heating

2018 ◽  
Vol 773 ◽  
pp. 152-156
Author(s):  
Chih Hsiung Shen ◽  
Shu Jung Chen ◽  
Shih Hao Lin
Keyword(s):  
Temperature Drop ◽  
Second Phase ◽  
Vacuum Measurement ◽  
Self Heating ◽  
Custom Design ◽  
Wide Range ◽  
Vacuum Sensor ◽  
Cmos Mems ◽  
Thermoelectric Sensor ◽  
Mems Process

This paper proposes a new vacuum sensor with CMOS Metal-N-Poly thermoelectric materials which works for both thermoelectric sensing and resistive heating. A new method of vacuum measurement with self-heating is proposed based on the dual phases of heating and sensing for the same element which is realized with CMOS thermoelectric sensor. Using the TSMC 0.35 μm CMOS-MEMS process, the proposed thermoelectric sensor is designed and fabricated with standard CMOS materials of the 4th metal and N-polysilicon to form 64 pairs of central-symmetrical thermocouples. There is an air convection-sensing area at the center of membrane and is filled with array of micro-through-holes to enhance the effect of heat convection. When the air molecules move through the array of hole, the heat exchange will take away the heat to cause a temperature drop of sensing area which gives a weak voltage between the cold and hot end of the thermocouples. The heating of thermopile itself is designed at the first phase and sensing the output voltage at the second phase subsequently. According to a careful investigation of the measurement with a wide range of 10m~10k torr, our proposed sensing scheme based on a thermoelectric type sensor is proved for practical vacuum detection and most of all it is proved as a new approach to use a commercial thermopile without heater, which is easier to include than a special custom design.

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 Photoacoustic Imaging with Capacitive Micromachined Ultrasound Transducers: Principles and Developments

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3617 ◽  
Author(s):  
Jasmine Chan ◽  
Zhou Zheng ◽  
Kevan Bell ◽  
Martin Le ◽  
Parsin Haji Reza ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Signal To Noise Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Photoacoustic Signal ◽  
Motion Artifacts ◽  
Oxide Semiconductor ◽  
Ring Resonators ◽  
Ultrasound Transducers ◽  
Fabrication Technique ◽  
Acoustic Techniques

Photoacoustic imaging (PAI) is an emerging imaging technique that bridges the gap between pure optical and acoustic techniques to provide images with optical contrast at the acoustic penetration depth. The two key components that have allowed PAI to attain high-resolution images at deeper penetration depths are the photoacoustic signal generator, which is typically implemented as a pulsed laser and the detector to receive the generated acoustic signals. Many types of acoustic sensors have been explored as a detector for the PAI including Fabry–Perot interferometers (FPIs), micro ring resonators (MRRs), piezoelectric transducers, and capacitive micromachined ultrasound transducers (CMUTs). The fabrication technique of CMUTs has given it an edge over the other detectors. First, CMUTs can be easily fabricated into given shapes and sizes to fit the design specifications. Moreover, they can be made into an array to increase the imaging speed and reduce motion artifacts. With a fabrication technique that is similar to complementary metal-oxide-semiconductor (CMOS), CMUTs can be integrated with electronics to reduce the parasitic capacitance and improve the signal to noise ratio. The numerous benefits of CMUTs have enticed researchers to develop it for various PAI purposes such as photoacoustic computed tomography (PACT) and photoacoustic endoscopy applications. For PACT applications, the main areas of research are in designing two-dimensional array, transparent, and multi-frequency CMUTs. Moving from the table top approach to endoscopes, some of the different configurations that are being investigated are phased and ring arrays. In this paper, an overview of the development of CMUTs for PAI is presented.

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.

scholarly journals Bitstream Photon Counting Chirped AM Lidar with a Dual Unipolar Signal

2020 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Phase I ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Sinusoidal Signal ◽  
Oxide Semiconductor ◽  
Quadrature Phase ◽  
Simulation Results

This paper is a follow-up to three previous papers: the first introducing the new Bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with the unipolar Digital Logic Local Oscillator (DLLO) concept, the second introducing the improvement thereof using the bipolar DLLO, and the third introducing the improvement of digital In-phase and Quadrature-phase (I/Q) demodulation.In that previous work, the signal was a single unipolar chirped sinusoidal or square wave. This paper introduces a new bitstream PC-CAML transceiver architecture that combines two unipolar chirped signals, referred to as the dual unipolar signal, to form a single bipolar signal in the receiver. (patent pending) This bipolar signal is mixed with the bipolar DLLOs in the in-phase (I) digital mixing and quadrature-phase (Q) digital mixing channels for digital I/Q demodulation for improved signal-to-noise ratio (SNR) compared to that when using a single unipolar signal.The simulation results presented in this paper indicate an SNR improvement for the dual unipolar chirped sinusoidal signal bitstream PC-CAML compared to that of the unipolar chirped sinusoidal signal bitstream PC-CAML (both with bipolar DLLOs and digital I/Q demodulation) of from about 3 dB to about 6 dB for signals below the onset of receiver saturation, and an improvement for maximum achievable SNR of about 13 dB if the receiver is allowed to saturate.The bitstream PC-CAML with a dual unipolar signal and bipolar DLLOs with digital I/Q demodulation architecture discussed in this paper adds complexity to the transmitter and receiver compared to the architectures presented in the previous papers. Whether or not this additional complexity is worth the improved SNR will have to be decided as part of system trade studies for particular systems and their applications.However, the new architecture still retains the key advantages of the previous bitstream PC-CAML architectures since it still replaces bulky, power-hungry, and expensive wideband RF analog electronics in the receiver with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous standard PC-CAML systems.This paper introduces the dual unipolar signal and bipolar DLLOs with digital I/Q demodulation transceiver architecture for bitstream PC-CAML, and presents the initial SNR theory with comparisons to Monte Carlo simulation results.

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.

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

2021 ◽  
Author(s):  
Daniel Popa ◽  
Richard Hopper ◽  
Syed Zeeshan Ali ◽  
Matthew 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

Abstract The 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 • 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 • 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 Sensors.

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