A study on a fabricated piezoresistive micro-electro-mechanical systems (MEMS) cantilever for a mass-based sensor has been carried out to enhance sensor sensitivity by introducing the stress concentration region (SCR). Three types of SCR geometry designs were first analysed using finite element analysis (FEA) software ANSYS ® to study the effect of stress and its distribution when varying mass is applied at the free end. FEA results show that the rectangular SCR design has the highest stress. Then, the length of rectangular SCR is varied from 1000 m (A1) to 3000 m (A3) to study the stress distribution along the cantilever. The piezoresistive MEMS cantilever with rectangular SCR A3 produced the highest stress and was thus selected for fabrication along with the piezoresistive MEMS cantilever without SCR. From the testing results, the piezoresistive MEMS cantilever with rectangular SCR A3 successfully enhanced sensitivity by 1.97 times as compared to the piezoresistive MEMS cantilever without SCR when varying mass is applied. Therefore this SCR approach appears to be suitable for enhancing the sensitivity of a mass-based piezoresistive MEMS cantilever sensor.

Enhancing the sensitivity of a mass-based piezoresistive micro-electro-mechanical systems cantilever sensor

© 2012 Firdaus et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. High Sensitive Piezoresistive Cantilever MEMS Based Sensor by Introducing Stress Concentration Region (SCR)

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High Sensitive Piezoresistive Cantilever MEMS Based Sensor by Introducing Stress Concentration Region (SCR)

A study about the piezoresistive Micro-Electro-Mechanical Systems (MEMS) cantilever for a chemical sensitive mass based sensor has been carried out to enhance sensor sensitivity. The sensitive region attracts the CO2 molecules there by introducing the stress concentration region (SCR). Three types of SCR geometry designs were first analysed using Intellisuite software to study the effect of stress and its distribution when varying mass is applied at the SCR. The results showed that the rectangular SCR design has the highest stress and showed a linear relation too when compared to the other types. Then, the length of rectangular SCR is varied to study the stress distribution along the cantilever. The piezoresistive element was then placed at various positions to obtain the highest stress resulting due to the deflection of the cantilever. The impact due the SCR was also analysed. The testing results of this piezoresistive MEMS cantilever with rectangular SCR had successfully enhanced sensitivity compared to the piezoresistive MEMS cantilever without SCR when varying mass is applied. Therefore this SCR approach appears to be suitable for enhancing the sensitivity of a massbased piezoresistive MEMS cantilever sensor. General Terms CO2 Gas Sensor using MEMS

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Peizoresistive Mems Cantilever based Co2 Gas Sensor

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Resonant frequency characterization of a novel mems based membrane engine

We report on a bridge structure PZT [Pb(ZrxTi1- x)O3] thin film microtransducer with proof mass that has been fabricated successfully at the Microtechnology Laboratory (MTL) of the University of Minnesota. The bridge microtransducer is made on silicon wafer using bulk micromachining of microelectromechanical systems (MEMS) and special techniques for deposition of a PZT thin film. The bridge is 300 micrometers wide, 1000 micrometers long, and a few micrometers thick. A proof mass made from the silicon wafer is loaded under the bridge at the central region, its area is 300 X 300 square micrometers and its thickness is 475 micrometers (same as the wafer). Used as an accelerometer, the microtransducer is calibrated using a Vibration Test Systems (VTS), which is a commercial accelerometer calibration instrument. The sensitivity of the microtransducer is constant over the range of frequencies from zero to 10 kHz, 240(mu) V/g at 0.5g with a dc bias voltage of 0.2 volts and a deviation of 5%. The Brownian thermal noise equivalent acceleration is 9.072(mu) g/(root)Hz. Design of a bridge structure with mass loading is modeled using ANSYS. Simulation analysis shows that the fundamental natural frequency of the microtransducer is 11.352 kHz, which is close to the measured resonant frequency of 12.28 kHz.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Bridge structure PZT thin film microtransducer with mass loading

MEMS micropumps, based on PZT membranes have been designed and fabricated at the Microtechnology Laboratory of the University of Minnesota for use in fluid flow control, and as chemical and pressure sensors. Design, fabrication and numerical analyses of the PZT cantilever beams were presented at the MSM99, and are now extended to new MEMS devices; specifically reactive ion etched (RIE) bulk micromachined PZT membranes. Four major geometries including square, rectangular, circular and elliptic devices with different sizes have been successfully fabricated. The main advantage of the new devices is in providing more resonant points than the microcantilever beam, thus creating a larger working interval. Numerical studies have been carried out by using ANSYS Finite Element software. Numerical results compared well with the experimental findings.

https://briefs.techconnect.org/wp-content/volumes/MSM2000/pdf/T42.04.pdf

K S Yigit

Papers

Design, Fabrication and Experimental-Numerical Study of PZT Sensors