Current-density patterns induced by avalanche injection phenomena in high-voltage diodes during turn-off

Abstract

The turn-off behavior of two types of high-voltage diodes is investigated by means of numerical simulations. Basic self-organized structures appearing as transient patterns during the turn-off period are quasi-stationary or traveling current-density filaments and periodic current-density distributions. Additionally, we find evolution of more complex patterns that can be considered to be a superposition of basic structures. Examples of such complex structures are presented and mechanisms leading to their evolution are discussed.

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

“…This explains the reduction of v a in the 1D case [5], but it also indicates that the moving direction of the anodeside front can not change under dynamic avalanche conditions. Furthermore, the higher v a in 2D and 3D structures results from the fact that the total current density j total in the filament is much higher than far away from the filament [3]. At higher front velocities v a , a traveling filament arises [8].…”

“…This has been demonstrated by various simulations [5]. However, in 2D simulations, dynamic avalanche appearing in filaments leads to an increase of v a [3]. The aim of this work is to expand the consideration of front-velocities [5] for the 2D and 3D cases (Section II).…”

“…During the reverse-recovery period, an anode-side and a cathode-side depletion layer with a charge-carrier plasma layer in between may evolve (for example [2], [3]). A hot-spot failure of the diode may be caused by current filaments arising in these depletion layers.…”

“…A hot-spot failure of the diode may be caused by current filaments arising in these depletion layers. Cathode-side filaments are typically locally fixed [3] and may lead to the destruction of diodes according to a stability approach [4]. For a one-dimensional (1D) case [5], the vertical front-velocities of the plasma layer are expressed by: v a = j n,ava − j n,a qn a ,…”

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

“…In recent years, the carrier lifetime control technologies mainly include the high energy electron irradiation resulting in a uniform lifetime distribution [6][7][8], and the proton or He 2+ irradiation providing a local low lifetime distribution [8][9][10][11]. The carrier lifetime distribution determines the on-state plasma distribution in the n − base, which can influence the extraction velocity of the plasma and the power loss during reverse recovery, and what's more, it even influences the formation and movement of current filaments under dynamic avalanche [12][13][14]. This is very important for the device reliability.…”