The CIBH Diode - Great Improvement for Ruggedness and Softness of High Voltage Diodes

The concept of controlled injection of backside holes (CIBH) is a novel and path breaking method for the optimization of the electrical characteristics of diodes. Buried p-doped layers at the cathode side of the diode inject holes in the base region during reverse recovery. Due to this injection the snap-off of the diode can be suppressed effectively. The main intention of this paper is to take advantage of the CIBH concept for designing a fast switching 3.3 kV diode with low V_f, low switching losses, high ruggedness and strongly improved softness. A new promising effect of the CIBH design, which we call DSDM (dynamic self damping mode), further increases the soft reverse recovery behavior and results in a nearly snap-off free diode characteristic.