Finite element modelling of piezoelectric micro-cantilever as Gas sensor (original) (raw)
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IJERT-Design and Fabrication of Cantilever MEMS Sensor Model for Electro-Chemical Gas Sensor
International Journal of Engineering Research and Technology (IJERT), 2020
https://www.ijert.org/design-and-fabrication-of-cantilever-mems-sensor-model-for-electro-chemical-gas-sensor https://www.ijert.org/research/design-and-fabrication-of-cantilever-mems-sensor-model-for-electro-chemical-gas-sensor-IJERTV9IS070262.pdf The exponentially rise in technologies have broadened the horizon of human life to exploit enhanced systems and solutions to make precise, timely and optimal decision. Undeniably, majority of the scientific contributions intends to make human society and allied industrial activities productive and efficient. The up-surging industrial development and complex operating environments, especially chemical industries, strategic warehouses or infrastructures where there can be the presence of different gases in direct or indirect form, demands a robust and efficient sensing solution to avoid any unexpected hazardous. Considering the significance of a robust and efficient gas sensing technology, in this manuscript the predominant emphasis has been made on exploring different technologies and allied mechanisms to perform gas sensing. Being a survey paper, in this paper key gas sensing technologies, including cantilever based Micro-Electro-Mechanical System (MEMS) have been studied. Observing majority of the researches, it can be found that cantilever MEMS can be the potential solution for gas sensing and analytes identification in a complex operating environment. However, the design, shape and materials of the cantilever MEMS often decides efficacy to perform sensing. This survey revealed that to achieve optimal gas sensing solution, enhanced semiconductor cantilever design with optimized shape, and materials can yield sensitive and power efficient gas sensing solution. Considering the fact that the shape and materials have the combined impact on overall efficiency, certain machine learning approaches such as Artificial Neural Network or even enhanced algorithms can be considered. Obtaining an optimal solution with suitable materials, shape and size of cantilever which can be stated to be a NP-hard problem, machine learning or stochastic prediction models can also be considered. Structurally, the optimal setup with Piezo-resistive cantilever MEMS with optimal shape, size and coating material can enable optimal gas sensing performance of the micro-cantilever structure. Moreover, the selection of coating materials can help achieving deflection sensing or surface strain to perform flow rate assessment.
Simulation and design of piezoelectric microcantilever chemical sensors
2005
This paper presents an analytical modeling of a piezoelectric multi-layer cantilever used as a micro-electro-mechanical-system (MEMS) chemical sensor. Selectively coated microcantilevers have been developed for highly sensitive chemical sensor applications. The proposed piezoelectric chemical sensor consists of an array of multi-layer piezoelectric cantilevers with voltage output in the millivolt range that replaces the conventional laser-based position-sensitive detection systems. The sensing principle is based upon changes in the deflection induced by environmental factors in the medium where a microcantilever is immersed. Bending of the cantilever induces the potential difference on opposite sides of the piezoelectric layer providing an information signal about the detected chemicals. To obtain an application specific optimum design parameters and predict the cantilever performance ahead of actual fabrication, finite element analysis (FEM) simulations using CoventorWare (a MEMS design and simulation program) were performed. Analytical models of multi-layer cantilevers as well as simulation concept are described. Both mechanical and piezoelectric simulation results are carried out. The cantilever structures are analyzed and fabrication process steps are proposed.
Environmental sensors based on micromachined cantilevers with integrated read-out
Ultramicroscopy, 2000
An AFM probe with integrated piezoresistive read-out has been developed and applied as a cantilever-based environmental sensor. The probe has a built-in reference cantilever, which makes it possible to subtract background drift directly in the measurement. Moreover, the integrated read-out facilitates measurements in liquid. The probe has been successfully implemented in gaseous as well as in liquid experiments. For example, the probe has been used as an accurate and minute thermal sensor and as a humidity sensor. In liquid, the probe has been used to detect the presence of alcohol in water.
This article describes the modeling, simulation and experimental verification of the properties of five different macro-scale piezoelectric (PZT) cantilevers for the prediction and deduction of properties of their micro-scale counterparts in relation to their mass sensitivity. In order to investigate the relationship between resonant frequency, quality factor and mass sensitivity, piezoelectric cantilevers of different lengths from 40 mm to 10 mm are utilized keeping the other parameters constant. On the basis of the test definition and the feedback received from a reference accelerometer is mounted on shaker table, the control signal is generated by the controller unit, and the signal is amplified using an IMV MA1 type amplifier that can produce a maximum output. Then the amplified signal is fed to the shaker unit. The output from the piezoelectric is recorded and analyzed using a DEWE-3023-dsa-x type dynamic signal analyzer. Different masses are attached to the free end of the cantilevers and the change in resonance frequency measured. The main advantages of cantilevers as sensing mechanisms are their high sensitivity, low cost, high response, and low power consumption. Through this study we discover that the sensitivity is a strong function of attached mass, highest sensitivity achieved at law attached mass and stumpy PZT cantilever.
Gas sensing using embedded piezoresistive microcantilever sensors
Sensors and Actuators B-chemical, 2004
A novel gas sensor design has been developed using embedded piezoresistive microcantilever (EPM) technology. In this design, a small piezoresistive microcantilever is embedded or partially embedded into a sensing material that swells slightly upon analyte exposure. This swelling is measured as a simple resistance change in the piezoresistive cantilever, and thus the analyte is detected. Here, we have used an Ni-containing polymer, poly(ethylene oxide), as the active sensing material. This EPM sensor is then used to detect the presence of carbon monoxide gas. For small exposures, the sensor is fully recoverable; however for very large exposures, irreversible chemical changes in the polymeric sensing material occur.
Performance Analysis of Cantilever Based MEMS Sensor for Environmental Applications
In this paper we presents a MEMS (Micro-electromechanical System) cantilever based humidity sensor for various applications such as environmental monitoring, electronics, agriculture and biomedical fields. The main focus of this paper is to design, simulate and analyze the performance of MEMS based T shaped microcantilevers using different sensing materials such as Al2O3, Porous Silicon and Poly Silicon. The simulation is done through finite element tool and parameters like the maximum induced stress; deflection and sensitivity of the diaphragms have been analyzed using the software INTELLISUITE version 8.7. The change in humidity element is bending of the microcantilever that modifies the measured displacement between the substrate and the microcantilever. This change in displacement gives the measure of amount of water vapor present in that environment. The outcome of these studies can be used to enhance the sensitivity of these devices. Here we observe that the best sensitivity output responses are obtained in the range of 10%RH to 100% RH and also the maximum sensitivity of 21.85 (m/%RH).
Geometry optimization of uncoated silicon microcantilever-based gas density sensors
In the absence of coating, the only way to improve the sensitivity of silicon microcantilever-based density sensors is to optimize the device geometry. Based on this idea, several microcantilevers with different shapes (rectangular-, U-and T-shaped microstructures) and dimensions have been fabricated and tested in the presence of hydrogen/ nitrogen mixtures (H 2 /N 2 ) of various concentrations ranging from 0.2% to 2%. In fact, it is demonstrated that wide and short rectangular cantilevers are more sensitive to gas density changes than U-and T-shaped devices of the same overall dimensions, and that the thickness doesn't affect the sensitivity despite the fact that it affects the resonant frequency. Moreover, because of the phase linearization method used for the natural frequency estimation, detection of a gas mass density change of 2 mg/l has been achieved with all three microstructures. In addition, noise measurements have been used to estimate a limit of detection of 0.11 mg/l for the gas mass density variation (corresponding to a concentration of 100 ppm of H 2 in N 2 ), which is much smaller than the current state of the art for uncoated mechanical resonators.
Polymer-based gas sensor on a thermally stable micro-cantilever
2010
Polymer-based sensors have several advantages for gas detection. They can utilize different polymer composite films as their sensing materials, which results in their ability to respond to a wide range of volatiles. However, it is shown that polymer-based sensors suffer from a large temperature sensitivity that causes shift in their volatile response. To overcome this disadvantage, a new design of interdigitated electrodes on a micro-hotplate is proposed. This detector employs a micromachined sensor structure on silicon wafer that maintains a constant temperature throughout the device. Different micromachined sensor structures and substrates were investigated as candidates for constant temperature platforms. COMSOL simulations were performed to investigate the heat transfer profile. Sensor structure and dimensions together with the heater structure were optimized based on the simulation results.
Defence Science Journal, 2016
Micro-electro-mechanical systems (MEMS)-based cantilever platform have capability for the detection of chemical and biological agents. This paper reports about the finite element method (FEM) based design and simulations of MEMS-based piezoresistor cantilever platform to be used for detection of chemical and biological toxic agents. Bulk micromachining technique is adopted for the realisation of the device structure. MEMS piezoresistive biosensing platforms are having potential for a field-based label-free detection of various types of bio-molecules. Using the MEMMECH module of CoventorWare® simulations are performed on the designed model of the device and it is observed that principal stress is maximum along the length (among other dimensions of the micro-cantilever) and remains almost constant for 90 per cent of the length of the micro-cantilever. The dimensions of piezoresistor are optimised and the output voltage vs. stress analysis for various lengths of the piezoresistor is performed using the MEMPZR module of the CoventorWare®.
Modeling of Piezoresistive Cantilevers for Chemical Sensing
International Journal of Engineering Applied Sciences and Technology
This paper presents and analytical model to provide good results for cantilevers with point load at free end and to describe the micro cantilevers with surface stress. It has been shown that the width of the cantilever has to be increased to optimize the sensitivity. The placement of the piezoresistor was found to be in the centre of the cantilevers clamped end and the area of the piezoresitor should be minimized.