3D MOSFET Simulation

Hello everyone, I made my own 3D FinFET structure using gmsh & geo file. but it’s hard to simulation this FinFET and get Id_Vg curve with devsim software.

there are some questions.

  1. Is it ok to simulate 3d mosfet with the way of simulation 2d MOSFET? I’ve simulated 2D MOSFET using common “devsim” way (just with gmsh_mos2d.py & ramp.py files)

  2. If it is ok, How can i avoid “Convergence Failure” error ? everytime i try to get Id_Vgs curve, “Convergence Failure” error occurs at solve(type=“dc”, absolute_error=1.0e30, relative_error=1e-5, maximum_iterations=30) line or rampbias function lines. l’ve already read some topics about this error and i tried all of solution, but there was no change.

  3. If it is not ok, please let me know how to Simulate 3D MOSFET and get some Id Curves.

Thank you everyone.

Hi @yoonbeom
There has been a 3D MOSFET example coming from Juan:
I don’t know if you had seen it. Hope it can help you.

Hello @yoonbeom

Thanks for sharing your work. Please see the project that @ghost has shared the link. The accompanying paper is:


In the paper, we did not use gmsh for the 3D result. However, there are some advanced mobility models implemented in the simulation files.

I suggest looking into the possibility of using mesh refinement in Gmsh, as is shown here:


The scripts are capable of writing background meshes to guide 3D and 2D refinement in Gmsh. Having improved refinement should help convergence.

I suggest to start by working with the simplest possible device physics, before working with advanced mobility models.