Eror:Failed convergence


I have an error in device. This error is " Drift-diffusion\Poisson Newton solver failed to convergence".
I have fixed many other errors that depended on the grid step and the calculation method, but I can’t to fix this problem.

Can you help me to solve it, please?
I am attaching a file solver.


Hi @o.kulbachynskyi

Thank you for posting your question. Given the error message it seems that the simulation stops around 3.5 V. Since the current 2D simulation doesn’t replicate the ring structure that you might have as a reference (the structure is uniformly extended in the third direction), the operating voltage and performance can differ from expectation. You might be able to slightly further the convergence by increasing the value for global iteration limit (currently 110). Looking into your simulation I have further comments which could be useful:

  • The imported generation data (two objects) are not averaged along the x axis. This seems necessary as you are performing a 2D x-normal simulation. You can refer to the vertical photodetector article as an example.

  • The fermi statistics in the advanced settings needs to be enabled as high values for doping is used. More information about this can be found in this post.

  • The value for minimum mesh edge length can probably be increased at this stage (e.g. to 30 nm). This will reduce the meshing time, making troubleshooting and obtaining initial results more convenient.

Kind regards