Charge carrier transport and deep levels recharge in avalanche $S$-diodes based on GaAs

Carrier transport and deep-level recharging in semiconductor avalanche $S$-diode structures have been investigated. Gallium-arsenide $n^+$–$\pi$–$\nu$–$n$ structures with the diffusion distribution of deep iron acceptors have been studied. It has been found by solving the continuity and Poisson equations with the use of a commercial software that the electron injection affects the avalanche breakdown voltage and the spacecharge region broadens due to capture of avalanche holes on negative iron ions in the $\pi$-region. It is demonstrated by comparing the results of numerical calculation with the experimental data that the $S$-shaped $I$–$V$ characteristic of the diffusion avalanche $S$-diodes cannot be explained within the previously proposed mechanism of capture of avalanche holes on the deep iron levels.