Mechanisms of formation of N–S transition in nonisothermal I–V characteristics of a p–i–n diode

On the basis of the self-consistent model of transport processes in the semiconductor p – i –n diode during its self-heating under conditions of limited heat sink, the mechanisms of unusual effect—the formations of N–S transition in nonisothermal I–V characteristics of the device were numerically analyzed. It is established that such an effect is caused by a pronounced temperature reduction of the mobility of carriers in the high-resistivity base and the injection-level saturation at the current densities J > 300–500 A/cm 2 . The saturation is attained due to the Auger recombination or the leakage of carriers from plasma into heavily doped emitter layers, the integrated current of which, as a rule, exceeds the recombination integrated current in the base under these conditions. The Auger recombination in the anode emitter also starts to play an appreciable role in the injection-level restriction in the base if the impurity concentration becomes higher than 10 18 cm −3 in there.