Influence of surface properties on the fracture of MEMS beams

Tuncay Alan, Alan Zehnder

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

Abstract

The effect of surfaces on the fracture strength statistics of Si MEMS beams is investigated through experiments and simulations. 180 nm thick, doubly clamped beams were fabricated from single crystal silicon (111) using photolithography and wet etching. The surfaces of the beams were varied by using two different aqueous base etchants, KOH and TMAH; the latter resulted in much smoother surfaces with smaller mean step heights than the former. The RMS roughness values were 2.3 nm for KOH and 0.8 nm for the TMAH etch. The experiment consisted of loading the samples with a carefully calibrated AFM cantilever until fracture. The Weibull strengths were estimated to be 12.8 GPa for beams with rough surfaces and 15.7 GPa for beams with smooth surfaces. The dependence of fracture strength on surface was analyzed using a Monte-Carlo simulation. Typical KOH and TMAH surface profiles were measured and used to generate simulated surfaces. A corner stress singularity approach was used to calculate strength statistics that are compared to experimental results.

Original languageEnglish
Title of host publicationProceedings of the 2006 SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006
EditorsEddie O'Brien
Place of PublicationUSA
PublisherElsevier
Pages1872-1879
Number of pages8
Volume1
ISBN (Print)091205395X, 9780912053950
Publication statusPublished - 31 Oct 2006
Externally publishedYes
EventSEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006 - Saint Louis, MO, United States of America
Duration: 4 Jun 20067 Jun 2006

Publication series

NameProceedings of the 2006 SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006
Volume4

Conference

ConferenceSEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006
CountryUnited States of America
CitySaint Louis, MO
Period4/06/067/06/06

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