Khashayar Ghaffari
Ansys Employee

Hello Eitan,

Thank you for reaching out and providing detailed information about the problem and your settings. Solving errors similar to what you have shared will require some troubleshooting. Based on the information available I have the following recommendations:

1- Confirming where the error is coming from: As you suggested this is most likely related to the very thin sub nano-meter layer, or similarly the large aspect ratio (feature size vs total simulation region size). However, to be sure, please disable the "2D layers" and confirm whether you can obtain a mesh and run for this version of your project.

2- Verify with a simpler version: There seems to be a uniformity in the third direction. If possible, I advise switching to 2D simulation to make the meshing less challenging. When successful you can switch back to 3D.

3- Mesh size: Assuming there are no local mesh constraints added to your project, the current settings opt for a minimum edge length of 20 nm while your 2D layers are sub nanometers. I suggest:

A) try reducing the minimum edge length in the solver's settings or adding local mesh constraints for the layers with smaller values.

B) the issue might be related to the large aspect ratio. In that case Increasing the maximum and minimum mesh edge length will be helpful. I would suggest testing this if 3.A doesn't work.

4- Finally, switching the volume meshing for 3D simulation could be helpful. Hybrid (your current choice) and advancing front methods could better success in generating a mesh for structures with thin geometries. More information about this option is provided in this article:

Let us know if you have any questions as you make further progress here.

Best regards,