Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

buckling of a fixed mems membrane with initial stress applied

Please login with a confirmed email address before reporting spam

Hello, I am a new Comsol user and I have a problem with a simulation of a multilayer vcsel mems membrane. The simulated data is different form the meassured one. The geometry of my structure is a four-leg membrane with a round plate in the center (plate diameter=120um, leg width=60um, leg length=140um)

example: ej.iop.org/images/0268-1242/28/1/012001/Full/sst446281f1_online.jpg

The membrane has 23 layers (Si3N4 and SiO2 alternately) of ca. 200nm thickness each. The legs are fixed at their ends (side surfaces). Each layer is prestressed (SiO2: -100MPa, Si3N4(bottom layers): 50MPa, Si3N4(upper layers): -160MPa). This Initial Stress makes the membrane buckle upwards. The experimental result is a deformation of 4.5 um (in the center of the memrane) . The simulation result is 1um.

I am using mems module, 3d geometry, application is solid mechanics, linear elastics material model, including geometric nonlinearity (large dimensions: on) and use nonlinear solver.

I would be very thankful for any hints.

0 Replies Last Post 28 oct. 2013, 06:44 UTC−4
COMSOL Moderator

Hello Szymon Sowizral

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.