Analysis of charge carrier multiplication events in NPT and PT-diodes triggered by an ionizing particle

We report on the modelling and numerical simulation of an ion irradiation experiment employed for characterizing the robustness of discrete power devices against cosmic rays. On the basis of cylinder-symmetrical simulations, we analyse the response of a non-punch-through (NPT) diode to an ionizing particle penetrating the device. The simulations visualize and demonstrate the temporal and spatial evolution of the electric field and the carrier densities. Another result is the accumulated charge generated by the impact of one single ion in the interior of the device. The simulated values conform well with recently reported experimental data. Simulating the device response of a punch-through (PT) diode shows that charge multiplication events, which unavoidably occur at sufficiently large reverse voltages, can lead to the destruction of the device. Moreover, our simulations and experiments also indicate that PT diodes exhibit higher robustness, against cosmic radiation in comparison to NPT diodes.