A New Analysis on Reduction of Undesired Beam Bending in Electrostatic Comb Drive MEMS Actuator

Mukherjee, B and Swamy, KBM and Sen, S (2020) A New Analysis on Reduction of Undesired Beam Bending in Electrostatic Comb Drive MEMS Actuator. In: IEEE Transactions on Instrumentation and Measurement, 69 (2). pp. 488-500.

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Abstract

In electrostatic comb drive-based sensors and actuators, often there is a possibility of nonparallel motion or bending in individual comb which considerably affects the device performance including pull-in characteristic. In this paper, we have presented a theoretical and experimental investigation to reduce such undesired beam bending in gap closing-type comb drive actuator. It has been envisaged that three key parameters, responsible for beam bending, are spring stiffness, beam stiffness, and number of actuation beams. Subsequently, a design guideline has been proposed to reduce the undesired bending by appropriate selection of these parameters. A specific comb drive actuator having multiple actuation regions with varying number of beams is designed, simulated, and analyzed using a semianalytical approach and FEM tool. Further, the structure is fabricated by establishing a silicon-on-insulator (SOI)-based single mask fabrication process and tested with an in-house experimental setup. The theoretical predictions are validated with the experimental results to demonstrate how the undesired beam bending can be reduced significantly by suitable selection of number of actuation combs for a given ratio of spring and beam stiffness. The proposed guidelines enable the micro-electromechanical system (MEMS) designers to cautiously choose the key parameters while designing in order to avoid the undesired comb bending and operate the device safely.

Item Type:	Journal Article
Publication:	IEEE Transactions on Instrumentation and Measurement
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	Copyright of this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Electromechanical devices; Electrostatics; Masks; MEMS; Silicon on insulator technology; Stiffness; Torsional stress, Beam bending; Comb-drive actuator; Electrostatic actuation; Micro electromechanical system (MEMS); Single-mask process, Electrostatic actuators
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	29 Jan 2020 10:38
Last Modified:	29 Jan 2020 10:38
URI:	http://eprints.iisc.ac.in/id/eprint/64396

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