On the formation of stationary destructive cathode-side filaments in p<inf>+</inf>-n<inf>&#x2212;</inf>-n⁺ diodes

Abstract

Analyzing the dynamics of current filaments is essential for a correct understanding of SOA limitations. Current filaments can occur during the reverse-recovery period of p + -n − -n + diodes. In this work, we apply the results from an analysis of the plasma-front dynamics for the one-dimensional case to conditions under which current filaments appear in the depletion layers due to dynamic avalanche. We show that the anode-side plasma front velocity is higher in the vicinity of the filament than far away from the filament center, favoring the evolution of a lateral traveling anode-side filament. Furthermore, we find that the cathode-side plasma front changes its vertical propagation direction when a dynamic avalanche in the cathode-side depletion layer causes current crowding. As a result, the cathode-side depletion layer in the vicinity of the filament decreases, favoring the formation of a standing cathode-side filament that may cause final destruction of the device. The analytical results are in good agreement with numerical simulations and results of previously published work.

Filament-induced thermomigration of an aluminum drop at the cathode-side of high-voltage power diodes

“…4b). It is therefore supposed that spikes can contribute to the destruction mechanism suggested in [2]. In [2], unrealistic hard-switching conditions were necessary to create a destructive filament in simulation.…”

“…It is therefore supposed that spikes can contribute to the destruction mechanism suggested in [2]. In [2], unrealistic hard-switching conditions were necessary to create a destructive filament in simulation. If once a filament has driven a spike by thermomigration from the cathode side into the base region of the diode, the diode can be destroyed during the next pulse.…”

“…However, a cathode-side filament tends to be fixed or to move only very slowly. Furthermore, it suppresses the transition into multiple cathode-side filaments [2]. Consequently, the appearance of a single cathode-side filament leads to a strong local heating at the cathode side which may lead to a melting of the metallization and finally to the formation of a buried aluminum eutectic.…”

Influence of carrier lifetime distribution on the current filament in high voltage diode

“…Recent studies have shown that the appearances of the filaments at the anode and cathode sides do not necessarily lead to the diode destruction, however, the eventual filament by a transition from avalanche-induced into thermally driven filament could cause the local temperature rise inside the device, this is an important factor of the device failure [3][4][5]. In order to improve the fast and soft recovery characteristic of high voltage diode, some technologies by improved structures and carrier lifetime controls were implemented.…”

Research to Improve the Forward Temperature Coefficient of FRD

“…As the lattice temperature raises, the carrier mobility, the electic field and the intrinsic carrier concentration will all be influenced. And as a result, it can be lead to the device failure, either in stationary or dynamic situation [3,4].…”