Experimental Observation of Delayed Impact-Ionization Avalanche Breakdown in Semiconductor Structures without p–n Junctions

We have experimentally studied the dynamics of impact-ionization switching in semiconductor structures without p – n junctions when subnanosecond high-voltage pulses are applied. Silicon n + – n – n + type structures and volume ZnSe samples with planar ohmic contacts exhibit reversible avalanche switching to the conducting state within about 200 ps, which resembles the well-known phenomenon of delayed avalanche breakdown in reverse-biased p + – n – n + diode structures. Experimental data are compared to the results of numerical simulations.