Micromachined capacitive pressure sensor with signal conditioning electronics (original) (raw)
Related papers
MEMS Capacitive Pressure Sensors: A Review on Recent Development and Prospective
—Recently MEMS Capacitive Pressure Sensor gains more advantage over micromachined piezoresistive pressure sensor due to high sensitivity, low power consumption, free from temperature effects, IC compatibility, etc,. The spectrum of capacitive pressure sensor application is increasing, hence it is essential to review the path of technological development and further prospective of micromachined capacitive pressure sensor. This paper focuses on the review of various types of capacitive pressure sensor principle, MEMS materials used in fabrication, procedures adopted in microfabrication for silicon and polymer material diaphragm, bonding and packaging techniques used. Selected result on capacitive sensitivity, effect of temperature on capacitive sensitivity was also presented. Finally, the development of smart sensor was discussed. MEMS Capacitive pressure sensor, Review on pressure sensor, CDPS, MEMS Fabrication, MEMS Material, pressure sensor, MEMS (Micro Electro Mechanical System)
A micro-capacitive pressure sensor design and modelling
Journal of Sensors and Sensor Systems, 2016
Measuring air pressure using a capacitive pressure sensor is a robust and precise technique. In addition, a system that employs such transducers lies within the low power consumption applications such as wireless sensor nodes. In this article a high sensitivity with an elliptical diaphragm capacitive pressure sensor is proposed. This design was compared with a circular diaphragm in terms of thermal stresses and pressure and temperature sensitivity. The proposed sensor is targeted for tyre pressure monitoring system application. Altering the overlapping area between the capacitor plates by decreasing the effective capacitance area to improve the overall sensitivity of the sensor (C/C), temperature sensitivity, and built-up stresses is also examined in this article. Theoretical analysis and finite element analysis (FEA) were employed to study pressure and temperature effects on the behaviour of the proposed capacitive pressure sensor. A MEMS (micro electro-mechanical systems) manufacturing processing plan for the proposed capacitive sensor is presented. An extra-low power short-range wireless read-out circuit suited for energy harvesting purposes is presented in this article. The developed read-out circuitry was tested in terms of sensitivity and transmission range.
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.
Energy Harvesting and Systems, 2021
In this paper, the improvement of the sensitivity of a capacitive MEMS pressure sensor is investigated. The proposed spring for the sensor can increase the sensitivity. Silicon is used as the substrate and gold and aluminium nitrate are used as the diaphragm and the dielectric layer, respectively. The dimensions of the diaphragm are 150 µm × 150 µm, which is suspended by four springs. The air gap between the diaphragm and the top electrode is 1.5 µm. The proposed structure is an efficient sensor for the pressures in the range of 1–20 kPa. By using the proposed design, the sensitivity of the MEMS sensor in 18 kPa has improved to 663 (× 10−3 pF/kPa).
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.
Capacitive pressure sensors based on MEMS, operating in harsh environments
2008
Micro-electromechanical systems (MEMS) capacitive pressure sensors operating at harsh environments (e.g. high temperature) are proposed because of SiC owing excellent electrical stability, mechanical robustness, and chemical inertness properties. The principle of this paper is, design, simulation. The application of SiC pressure sensors are in a harsh environments such as automotive industries, aerospace, oil/logging equipments, nuclear station, power station. The sensor demonstrated a high temperature sensing capability up to 400 °C, the device achieves a linear characteristic response and consists of a circular clamped-edges poly-sic diaphragm suspended over sealed cavity on a silicon carbide substrate. The sensor is operating in touch mode capacitive pressure sensor, The advantages of a touch mode are the robust structure that make the sensor to withstand harsh environment, near linear output, and large over-range protection, operating in wide range of pressure, higher sensitivity than the near linear operation in normal mode, so in this case some of stray capacitance effects can be neglected.
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.
Design and Analysis of Flexible Micromachined Touch Mode Capacitive Sensor for Pressure Measurement
2014
Now a days, capacitive touch sensors are widely used in consumer products like MP3 players, mobile phones and other portable devices. More and more, this technology is utilized in further application fields such as household appliances as well as automotive and industrial applications. The robustness, usability and cost efficiency are driving forces for the rapid development of capacitive touch sensors. In this paper, a simulation environment is created for fabricating capacitive sensors with different materials and then a performance analysis is carried out. \
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.
A low pressure meter based on a capacitive micro sensor
Physics Procedia, 2009
An implementation of a low pressure meter based on a capacitive micro sensor is exposed in this paper. In the first part, we presented the analysed sensor's structure and the developed theoretical model that permits to simulate the variation of its capacitance under applied absolute pressure. Keeping in mind that the variation of the sensor's capacitance is non linear and to allow for a direct measure of applied absolute pressures in a specified range and with a specified resolution, we proposed geometrical sizes for the design of the studied sensor. From the theoretical study, we deduced a suitable model for low pressure measurement. Considering this model, we developed in the second part an electronic associated conditioner using a differential sensing procedure that permits the direct display of low pressures with a desired resolution. An experimental setup with some results was shown by the end to confirm the validity of the proposed model.