PMUT array modelling

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Hi folks, I am trying to model displacement of PMUT array. Structure of model includes Sillicon on insulator wafer (SOI), Pt bottom electrode, 1.5um thick piezoelectric material (PZT-8) layer and top electrode. Part of SOI substrate removed (trenches etched from the bottom part to release PMUT elements). Thin layer of Si left below PZT. (akka unimorph with fixed edges). I have experimental data showing increased deflection within released part of PMUT (Etched trench has long oval shape, displacement pattern looks like half of ellipsoid). I created model in Comsol. Applied +5V to top electrode and ground to bottom electrode. Used this example as a reference: https://www.comsol.com/paper/modeling-and-analysis-of-thermal-bimorph-using-comsol-multiphysics-15585

I applied fixed constrained to entire substrate body, in this case displacement pattern look uniform and very small. I also tried to ally fixed constraint to outer boundary of substrate. in this case I see huge deformation of substrate that I don't see on experiment. Here is my model: https://drive.google.com/file/d/1hVWu5MwrB_JuRiNUaEuc152skwUdYRWK/view?usp=sharing

Could you please help with defining proper boundary conditions?

Thank you very much!

Stanislav



0 Replies Last Post Aug 26, 2024, 1:51 p.m. EDT
COMSOL Moderator

Hello Stanislav Udovenko

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