Electro-Thermal Simulation of Current Filamentation in 3.3-kV Silicon p+- n-- n+Diodes with Differenth Edge Terminations

We investigate the current filamentation behavior during reverse recovery in high-voltage 3.3-kV silicon p
⁺
- n
^-
- n
⁺
diodes with transient S-shape negative differential resistance characteristics. The transient I-U-bistability occuring in the reverse recovery period leads to a non-uniform, current distribution in the diodes when they are turned off with a high current rate di/dl. In this paper we compare the filament behavior of diodes without any edge termination with that of diodes providing a non-optimized JTE (junction termination extension), an optimized JTE, and a beveled edge termination by means of isothermal and electro-thermal device simulations. The observed differences are explained by analyzing the transient electric-field, current-density and temperature distributions in the devices