Design considerations for fast soft reverse recovery diodes

Both static and dynamic characteristics of power diodes are affected by carrier lifetime, thickness and resistivity of the base region, doping profiles, etc. The author presents results of the reverse recovery process simulation, considering the effects of carrier lifetime gradient and P-emitter concentration on the reverse recovery characteristics. For the simulation, a model considering a one-dimensional P⁺NN⁺ diode structure with assumed nonuniform carrier lifetime distribution, has been used. The results of computations have been discussed from the viewpoint of parameter improvement of both P⁺NN⁺ diodes and integrated diode structures of SPEED type or MSP type with particular emphasis on soft recovery