MEMS seminar TODAY at 3pm CISX Aud

Maryam Ziaei-Moayyed maryamzm at stanford.edu
Fri Jan 27 13:10:42 PST 2006


Winter 2006 MEMS Seminar

When: Friday 1/27/06  3-4 pm
Where: CISX Auditorium


TITLE: Stiction Force Estimation from Electrical and Optical Measurements on
Cantilever Beams

SPEAKER: Enakshi BhattacharyaDepartment of Electrical Engineering,
Indian Institute of Technology

ABSTRACT:

An estimate of stiction force, rather than the more commonly reported
surface energy, is necessary to design reliable surface micromachined
structures where stiction is a major cause of failure. In this work, we
discuss the modeling and estimation of the stiction force from simple I-V
measurements on cantilever beams that can be carried out even on packaged
devices. We also describe a technique to determine stiction force from a
cantilever beam array (CBA) that is normally used to estimate the surface
adhesive energy.

We have fabricated oxide anchored cantilever beams of polysilicon by surface
micromachining and measured the pull-in and pull-out voltages.  A model for
the stiction force was developed in terms of the pull-in and the pull-out
voltages both analytically and empirically using the commercial package
CoventorWare. This model can be used to estimate stiction force from
measured values of pull-in and pull-out voltages and the beam length and
does not require the value of Young’s modulus. We also discuss an
analytical model developed to calculate the stiction force from the
curvature of long collapsed cantilever beams in a cantilever beam array
(CBA) to determine process stiction. This requires the value of Young’s
modulus that is determined from pull-in measurements on shorter cantilever
beams released in the same process.



More information about the labmembers mailing list