Hi,

Running the 3D simulation can indeed be more challening in terms of convergence behavior given the added complexity of the problem. Here I suggest the following as you try to troubleshoot:

1 - Try reducing the simulation region area. For example try running the simulation for a smaller 3D portion. This might reduce the simulation complexity and allow you to obtain some initial results.

2 - Please make sure the first voltage step is 0 V; even if you are interested in the results at another bias, sweeping from 0V will help with convergence behavior as the solution at each bias relies on the previous step. Also, make sure the voltage steps are reasonably small given the problem at hand (e.g. 0.25 V or 0.5V).

3 - When sweeping the voltage do you obtain some partial results (for earlier bias points)? If so you can look into the available results, especially those at the last available bias point. This could give you insights in case there is a rapid increase in current or extreme electric field observed in a region.

4 - Try working with the convergence settings available in the advanced tab. For example increasing the iteration number and changing the solver type could be helpful.

Best regards