Microfabrication influence on the behavior of capacitive type MEMS sensors and actuators

Abstract

PurposeTo predict the influence of inherent microfabrication and operating environmental influences on the performance of capacitive type sensors and actuators so that one can tune the performance and carry out more realistic designs.Design/methodology/approachWhen the sensors and actuators are micromachined or microfabricated, they are subjected to special problems that are characteristic to microdimensions. The important concerns are the influence of microfabrication process on the material properties and influence of operating environment on the system behavior. Hence, this paper proposed a way of quantifying and modeling the influence of inherent limitations of microfabrication and operating environment for the better design of micromachined capacitive type sensors and actuators. The methodology applies the modeling the variation of the elastic property of the system due to above influences through elastic stiffening and weakening concepts. The approach includes the application of boundary conditioning concept through Rayleigh energy method.FindingsThe microfabrication process and electrostatic field can alter significantly both static and dynamic behavior of the device. The performance of the device could also be tuned through these influences.Research limitations/implicationsAs the displacement of the sensors is expected to be small, linear approach is applied. The sensitivity, output range, operating limits and natural frequencies of the sensor can be easily controlled by varying the process and operating environmental influences.Practical implicationsImproved and more realistic design of microfabricated capacitive type sensors and actuators for many applications, such as, pressure sensors, microphones, microspeakers, etc.Originality/valueA simple and easy way of modeling and quantifying the influence of process and operating environment was proposed for the betterment of design. The proposed design method can be applied for any micromachined or microfabricated capacitive type sensors and actuators so that varying sensitivities, output ranges and natural frequencies could be obtained. Over the last few years, newly emerging micro‐electro‐mechanical‐systems (MEMS) technology and micro‐fabrication techniques have gained popularity and importance in the miniaturization of a variety of sensors and actuators. The proposed technique is very useful in making the field of MEMS more matured as it attempts to model the problems that are unique to MEMS environment.