Efficient in-depth analysis and optimum design parameter estimation of MEMS capacitive pressure sensor utilizing analytical approach for square diaphragm (original) (raw)
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International Journal of Engineering Research and, 2015
In this paper three MEMS capacitive pressure sensors with different diaphragm geometries are designed and simulated. The sensors modelled have square, circular and rectangular diaphragms, with some fixed area. The diaphragm thickness of the three sensors is 63μm. The sensors are designed for high pressure sensing, over a range of pressure varying from 1Mpa to 100Mpa. The paper presents a rectangular diaphragm designed using a golden ratio of rectangle design widely used in image processing application with the ratio (b/a) equal to 1.618. Silicon<100> is used as a diaphragm material, because of its excellent properties. The paper provides a thorough analysis and discussion on different performance parameters for capacitive pressure sensing, such as the total displacement, capacitance, PRCC (Percentage Relative Change in Capacitance), electrical sensitivity. The design and simulation of the pressure sensors have been done based on Finite Element Method using Multiphysics simulation platform. Such kind of pressure sensors can be used in harsh environments involving high pressure applications.
Design and Simulation of MEMS Capacitive Pressure Sensor
Employing the MEMS technology, high sensitivities and resolutions have been achieved. Capacitive sensing uses the diaphragm deformation-induced capacitance change. In this paper, the design and simulation of conventional slotted and touch mode MEMS capacitive pressure sensor is proposed. The designed sensors are composed of a polysilicon diaphragm that deflects due to pressure applied over it, is accounted for modeling. The simulation results shows that the slotted MEMS capacitive pressure sensor achieves good sensitivity where as the touch mode MEMS capacitive pressure sensor achieves good linearity and large operating pressure range. The proposed MEMS capacitive pressure sensor demonstrated with diaphragm of side length 20 μm, gap depth 2 m is being modelled. The sensor exhibit a linear response for the pressure applied between 0 to 50 MPa. The simulation is carried out for different types of MEMS capacitive pressure sensor using COMSOL Multiphysics.
Microsystem Technologies, 2015
modes: normal mode and touch mode. In normal mode deflection of the plate is smaller than the height of cavity and in touch mode the plate touches the electrode placed at bottom. To achieve linearity characteristic, pressure sensing at high range and overload protection touch mode is designed. To clearly understand deflection of diaphragm, capacitance of electrode at each stage, sensitivity variation and linearity characteristic a step by step solution has been discussed and analyzed for both normal and touch mode capacitive pressure sensor.
In this paper, An analytical and simulation solution for touch mode Micro-electromechanical systems (MEMS) capacitive pressure sensor operating in harsh environment is proposed, The principle of the paper is to design, obtain analytical solution and compare the results with the simulation using coventor software for a circular diaphragm deflection before and after touch point. The material is considered to be used for harsh environment is SiC (Silicon Carbide), Because of SiC owing excellent electrical stability, mechanical robustness, and chemical inertness properties and the application of pressure sensors in harsh environments are, such as automotive industries, aerospace, oil/logging equipments, nuclear station, and power station. We are using coventor software for modeling and simulating of MEMS capacitive pressure sensor to optimize the design, improve the performance and reduce the time of fabricating process of the device. The device achieved a linear characteristic response and consists of a circular clamped-edges poly-SiC diaphragm suspended over sealed cavity on a poly-Sic substrate. The proposed touch mode MEMS capacitive pressure sensor demonstrated diaphragm ranging from 150ìm to 360ìm in diameter, with the gap depth from 0.5ìm to 6ìm and the sensor exhibit a linear response with pressure from 0.05 Mpa to 10 Mpa.
A Review of MEMS based Capacitive Pressure Sensor
This paper presents a review of the capacitive pressure sensor. Firstly, the different types of sensors available are compared. For applications requiring high sensitivity and very low effects due to temperature, the capacitive sensor is preferred. Various methods to change the capacitance are also compared, which leads to the conclusion that the method involving changing the distance between the plates has the highest sensitivity. The different diaphragms available are also compared in this paper. The result of the comparison shows that the square diaphragm is most suitable. Further study shows that the diaphragm with a bossed structure has the highest sensitivity and the lowest nonlinearity. After the structural analysis, the pull-in effect phenomenon present during anodic bonding is also studied. The analysis of the pull-in effect showed that the dimension of the sensor should be chosen such that the electrodes do not stick during the anodic bonding. Different capacitive sensing schemes are also shown in this paper. The parasitic capacitances and the noise are major factors limiting the performance of the sensor. So the sources and methods to mitigate such effects are also presented. The ASICs available for the conversion of the capacitance to voltage or digital output are compared based on different parameters.
In this paper the effect of the geometry of the silicon diaphragm used as moving plates in a Micro-electromechanical systems pressure sensor operating in harsh environments is studied. The principle of the paper is to propose a most ideally suitable geometry of the moving plate and bottom plate of parallel plate MEMS parallel plate capacitor which will have a better sensitivity when compared to the other geometric shapes of the moving plate diaphragm having the same area of cross section and thickness. The theoretical mathematical results are compared with the simulation using MEMS SOLVER software where the deflection dependency on the shape and size of the diaphragm is clearly visualized. As the sensitivity of the pressure sensor is dependent on the deflection of the moving diaphragm through the gap between the plates and the amount of deflection depends on the shape and size of the diaphragm the geometry of the diaphragm plays important role in the design of the sensor. The proposed pressure sensor parameters are radius of the diaphragm150µm 2 , and the thickness is 6µm and the gap between the plates is 10µm. The range of the sensor is 0-1MPa. Keywords-MEMS, capacitive pressure sensor, harsh environment, MEMS Solver, and diaphragm geometry.
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/sensitivity-analysis-of-mems-capacitive-pressure-sensor-with-different-diaphragm-geometries-for-high-pressure-applications https://www.ijert.org/research/sensitivity-analysis-of-mems-capacitive-pressure-sensor-with-different-diaphragm-geometries-for-high-pressure-applications-IJERTV4IS030671.pdf In this paper three MEMS capacitive pressure sensors with different diaphragm geometries are designed and simulated. The sensors modelled have square, circular and rectangular diaphragms, with some fixed area. The diaphragm thickness of the three sensors is 63μm. The sensors are designed for high pressure sensing, over a range of pressure varying from 1Mpa to 100Mpa. The paper presents a rectangular diaphragm designed using a golden ratio of rectangle design widely used in image processing application with the ratio (b/a) equal to 1.618. Silicon<100> is used as a diaphragm material, because of its excellent properties. The paper provides a thorough analysis and discussion on different performance parameters for capacitive pressure sensing, such as the total displacement, capacitance, PRCC (Percentage Relative Change in Capacitance), electrical sensitivity. The design and simulation of the pressure sensors have been done based on Finite Element Method using Multiphysics simulation platform. Such kind of pressure sensors can be used in harsh environments involving high pressure applications.
Evaluation for Diaphragm's Deflection for Touch Mode MEMS Pressure Sensors
In this paper, an analytical and simulation solution for touch mode Micro-electromechanical systems pressure sensor operating in harsh environment is proposed. The principle of the paper is to design, obtain analytical solution and compare the results with the simulation using finite elements analysis for a circular diaphragm deflection before and after touch point. By looking at MEMS devices, when the diaphragm starts touching the fixed electrode by applying loads, it will have a major effect on the overall performance of the device. Therefore, one should consider the effect of touch mode in the system to achieve good linearity, large operating pressure range and large overload protection at output. As of so far the effect of touch mode has not been evaluated efficiently in the literatures. The proposed touch mode MEMS capacitive pressure sensor demonstrated diaphragm with radius of 180 µ m , the gap depth of 0.5 µ m and the sensor exhibit a linear response with pressure from 0.05 Mpa to 2 Mpa.
IJERT-Comparative Analysis on Design and Simulation of Perforated Mems Capacitive Pressure Sensor
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/comparative-analysis-on-design-and-simulation-of-perforated-mems-capacitive-pressure-sensor https://www.ijert.org/research/comparative-analysis-on-design-and-simulation-of-perforated-mems-capacitive-pressure-sensor-IJERTV4IS070322.pdf MEMS sensor has gained popularity in automotive, biomedical, and industrial applications. In this paper, the design and simulation of conventional, slotted and perforated MEMS capacitive pressure sensor is proposed. Polysilicon material is used as diaphragm material that deflects due to applied pressure. Better sensitivity is the main advantage of conventional pressure sensor as compared with other two sensors and perforated pressure sensor achieves large operating pressure range. The proposed MEMS sensor demonstrated with diaphragm length 50um, gap depth 3um is being modelled. The simulation is carried out for different types of MEMS capacitive pressure sensor using COMSOL Multiphysics and Coventor ware.