Discussion Forum

Hello,

I am attempting to comprehend the impact of floating guard/field rings on the enhancement of breakdown voltage in p-i-n power diodes. To achieve this, I am simulating a structure outlined in the paper titled "Design and fabrication of planar guard ring termination for high-voltage SiC diodes" by Sheridan et al., published in Solid-State Electronics on August 1, 2000 (Volume 44, Issue 8, Pages 1367-1372).

While incorporating the floating guard/field rings into my simulation, I am encountering convergence issues. I suspect that these issues stem primarily from an incorrect boundary condition applied to the floating guard ring, specifically the pplus region 2 in my model, which is assigned an "insulation" boundary condition. Could you kindly suggest an appropriate boundary condition implementation to accurately simulate the floating guard/field rings in p-i-n diodes? I have attached my model for your reference.

I have already explored the possibility that the convergence problem may be due to meshing. Despite increasing the number of iterations to 1000 and using a very fine mesh, the simulation still fails to converge. Furthermore, when I introduce a metal contact to the guard ring boundary, the simulation works, but the breakdown voltage values obtained do not seem logical. For calculating the breakdown voltage, I am relying on the methodology detailed in the reference "Modeling of Avalanche Breakdown in Silicon and Gallium Nitride High-Voltage Diodes using COMSOL" by Dickerson et al., published on October 1, 2018 by Sandia National Laboratories (SNL-NM) in Albuquerque, NM, United States.

Thank you for your assistance in this matter.