Hello Wei,

Here are some excellent references for cantilever pull-in voltages:

   Osterberg, P.M.; Gupta, R.K.; Gilbert, J.R.; Senturia, S.D.
   "Quantitative models for the measurement of residual stress, Poisson
     ratio and Young's
    modulus using electrostatic pull-in of beams and diaphragms"
   Technical Digest. Solid-State Sensor and Actuator Workshop, 1994

   Osterberg, P.M.; Senturia, S.D.
   M-TEST: A test chip for MEMS material property measurement using
    electrostatically actuated test structures
   Journal of Microelectromechanical Systems, V. 6, p. 107, 1997

   Gupta, R.K.; Osterberg, P.M.; Senturia, S.D.
   Material property measurements of micromechanical polysilicon beams
   Proceedings of the SPIE - The International Society for Optical
    Engineering Microlithography and Metrology in Micromachining II , V.
    2880, p. 39, 1996

These papers present 2D and 3D simulation models of cantilever pull-in,
and calculate a closed-form equation that is highly consistent with
these models.

There can be a great deal of hysteresis in the pull-in voltage of a
cantilever beam. Much of this appears to be due to surface charging. For
a reference on this topic, please see:

   Jurgen Wibbeler; Gunter Pfeifer; Michael Hietschold
   "Parasitic charging of dielectric surfaces in capacitive
    microelectromechanical systems (MEMS)"
   Sensors and Actuators A 71 (1998) 74-80

Best wishes for all of your efforts.

-Craig McGray
 Dartmouth College




> Message: 4
> Date: Fri, 25 Jan 2002 11:40:47 +0000 (!!!First Boot!!!)
> From: "LEOW Cheah Wei" 
> To: 
> Subject: [mems-talk] electrostatic pull-in voltage for cantilever beam
> Reply-To: [email protected]
>
> Dear everybody,
>
>        can somebody post or point to some link on measured data for pull-in
> voltage of a
> 1) cantilever beam
> 2) bilayer cantilver beam (e.g. poly2 with metal from MUMPS and it is curved
> )
> 3) related structure
>      i'm interested in simulating/modeling the pull in voltage Vs beam
> length. The data will be very useful in verifying the result.
>
> thank you
>
> LEOW Cheah Wei
> master student
> Universiti Teknologi Malaysia
> http://www.geocities.com/cheah_wei