Reverse recovery in p-n junction diodes with built-in drift fields

This paper extends the earlier analysis of Moll, Krakauer and Shen of the reverse recovery of a symmetrical p-n junction diode with built-in retarding drift field in the base to the diodes in which the effect of bulk recombinations in the base is important. It is shown that the effect of bulk recombination becomes important if $\text{J}{}_{\mathrm{f}}\text{J}{}_{\mathrm{R}}\text{? 0.5}$ (J_F and J_R are the forward and the reverse currents respectively) even when the drift field is very strong. For very strong retarding fields, t_s vs ln $\text{(1 +}\text{J}{}_{\mathrm{F}}\text{J}{}_{\mathrm{R}}\text{)}$ plot is linear and has a slope very close to the minority carrier lifetime τ_B in the base even for small values of time. Hence, τ_B can be conveniently determined by this method for such diodes. Expressions for the charge left in the base at the end of the storage phase and for the decay of the current in the second phase are also derived and discussed.