Reply To: Program Termination Error in Charge

[kghaffari]

Hi,

Thank you for posting your question and providing detailed information. Since the more general instructions in the troubleshooting article haven’t been helpful, I can provide some specific suggestions, given the description of your problem. These will be modifications to identify the cause of error:

• Material bandgap: Convergence issues in CHARGE are more common for materials with wide bandgap. Can you try switching TiO2 and MoO3 to a material with smaller bandgap like silicon and run again? If the issue is related to the material, please ensure that the latest version of CHARGE is installed (2024R2) as we have made some improvements to convergence behavior for these materials recently.
• Mesh: As you suggested, I recommend testing different mesh values. Both increasing or decreasing the mesh refinement may be helpful. I would also test having local mesh objects targeting the two materials you mentioned (TiO2 and MoO3). However, please ensure that the change in mesh settings takes effect in the actual generated mesh. You can mesh (before running) the simulation and see if the numbers are making an impact. If not, try increasing max refine steps.
• Doping: Please switch the simulation to partition mode and select each doping object, to ensure the doping is applied to the intended region. The region of interest should be both included in the green box (defined by the doping object coordinates) and highlighted (impacted by Applicable Domain>volume type). Applying increased mesh refinement to areas with higher doping can be helpful.
• Imported generation: If the input power is very high convergence in CHARGE becomes more challenging. You can test reducing the scaling factor in the import object to examine its effect on convergence. Of course, if you are sure that the scaling factor corresponds to the operating input power of your device (and simulating with a smaller number is not helpful) you would need to keep the number. Still, knowing the impact of scaling factor can be helpful here.
• Initialization Error: I believe this is mentioned in the referenced article; starting the CHARGE simulation from a voltage other than zero makes the convergence more difficult to obtain. Please make sure the starting voltage is 0 and then sweep to your target bias value.

Hope these can be helpful. Please feel free to follow up with any updates. Best, Khash