Simultaneous determination of young's modulus and residual stress in PECVD a-SiC from postbuckling vibration of MEMS beams

Pratap, R and Behera, AR (2018) Simultaneous determination of young's modulus and residual stress in PECVD a-SiC from postbuckling vibration of MEMS beams. In: Symposium on Wearable Sensors and Systems 1 -and- Microfabricated and Nanofabricated Systems for MEMS/NEMS 14 - AiMES 2018, ECS and SMEQ Joint International Meeting, 30 September - 4 October 2018, Cancun, pp. 87-100.

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Abstract

For design of MEMS structures, an accurate measurement of material properties of thin films is necessary, which vary considerably due to process variations. In addition, performance of MEMS devices are often affected due to process induced residual stresses and even dimensional variations. Thus, it is essential that we develop techniques to determine these important material and structural properties from each complete fabrication process. In this work, we exploit the invariance of even modes of buckled beams w.r.t. Change in stress for decoupling effects of modulus and stress on dynamic characteristics of MEMS beams. This enables simultaneous estimation of Young's modulus and residual stress. The technique is demonstrated by estimating modulus and stress in amorphous silicon carbide thin films deposited by PECVD. Use of post-buckling analysis makes this technique useful for thin films with high compressive stresses. Since the proposed method does not involve electrostatic actuation, it is equally applicable to dielectric thin films.

Item Type:	Conference Paper
Publication:	ECS Transactions
Publisher:	Electrochemical Society Inc.
Additional Information:	The copyright for this article belongs to the Electrochemical Society Inc.
Keywords:	Amorphous silicon; Compressive stress; Elastic moduli; Electrostatic actuators; Residual stresses; Silicon carbide, Accurate measurement; Dielectric thin films; Dimensional variations; Electrostatic actuation; Fabrication process; Postbuckling analysis; Simultaneous determinations; Simultaneous estimation, Thin films
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	19 Aug 2022 05:14
Last Modified:	19 Aug 2022 05:14
URI:	https://eprints.iisc.ac.in/id/eprint/75977

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