I–V Characteristics of High-Power Diode Structures with Sharply Asymmetric Injection Ability of the Emitters

Diode structures with strong asymmetry of the injection ability of emitters are investigated. The ratio between the base-layer thickness and the ambipolar diffusion length in these structures is ~1. At a high current density, strong asymmetry of the injection ability of the junctions leads to the implementation of recently discovered diffusion, which is stimulated by quasi-neutral drift, along with the diffusion and quasi-neutral drift carrier-transport regimes that are conventionally taken into account. It is shown that, with an increase in the current density, the quasi-neutral drift carrier-transport region collapses. In this case, an S -shaped portion arises in the I – V characteristic of the diode even at a relatively small ratio between the base-layer width W and ambipolar diffusion length L .