Etch-induced stress failures of SiO sub(2) cantilever beams

Acute angles formed in the underlying silicon during anisotropic etching to free silicon dioxide cantilever beams are found to be the point of maximum stress during etch. Consequently, failures of the cantilever structure originate at these locations. The origin of this stress concentration is due t...

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Bibliographic Details
Published in:Sensors and actuators. A. Physical. 1998-10, Vol.70 (3), p.283-290
Main Authors: Shafai, C, Brett, M J, Hrudey, T M
Format: Article
Language:English
Online Access:Get full text
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Summary:Acute angles formed in the underlying silicon during anisotropic etching to free silicon dioxide cantilever beams are found to be the point of maximum stress during etch. Consequently, failures of the cantilever structure originate at these locations. The origin of this stress concentration is due to mechanical loading of the cantilever during etch, and this loading effect is smaller for shorter or narrower cantilevers. Finite element modelling of a partially etched cantilever microstructure, as used to predict the location of maximum stress, as well as the probable vector direction failures, will follow. Cantilevers free of etch-induced failure are fabricated by isotropic etching and by the modification of etch geometry through the addition of ribbed segments to the cantilever.
ISSN:0924-4247