Transmission electron microscopy investigation of dislocations in forward-biased 4H-SiC p–i–n diodes

Abstract

When a 4H-SiC p–i–n diode is operated under forward biasing, it rapidly degrades, and the degradation is accompanied by the generation of a high density of stacking faults in the active region of the device. In this letter, the partial dislocations bounding the stacking faults have been investigated by transmission electron microscopy. They are found to be in the form of single leading partial half-loops with a 13〈101̄0〉 Burgers vector that bound triangular-shaped stacking faults. Two sides of each faulted loop are bound by two partial dislocation segments lying along different 〈12̄10〉 directions, while the other edge of the triangular stacking fault is a surface (or interfacial) step. The core nature of the two segments has been determined by the technique of large-angle, convergent-beam electron diffraction, and found to be different: one has a silicon core, while the other has a carbon core.

Silicon carbide power‐device products – Status and upcoming challenges with a special attention to traditional, nonmilitary industrial applications

“…Efforts are directed today towards the improvement of both the reverse recovery behavior and the static losses. In addition, a lot of work is dedicated to the so-called bipolar forward drift phenomena in SiC diodes that result in a degradation of the on-state behavior under forward bias [5]. The root cause is understood (basal plane dislocations) and considerable progress was reported towards elimination of this effect [26].…”

“…In reality, the SiC technology is suffering somewhat from the fact that work on defect structures other than the famous micropipes started quite late. It commenced only a few years ago and was mainly triggered by the bipolar degradation effects first observed by ABB in SiC diodes [5].…”

Structural characterization of double stacking faults induced by cantilever bending in nitrogen-doped 4H-SiC

“…However, despite the high crystalline perfection of the wafers now available, the use of SiC still remains restricted because of the expansion of device-killer stacking faults (SFs) dragged by Shockley partial dislocations under forward biasing of bipolar devices [1][2][3][4][5][6][7][8][9][10][11]. In addition, the formation of double stacking faults (DSFs) bound by two Shockley partial dislocations during oxidation [12], annealing [13][14][15] or hightemperature processing [16] of highly nitrogen-doped 4H-SiC (10 18 -10 19 cm À3 ) has also been reported.…”

Planar defects in 4H-SiC PiN diodes

“…[1][2][3] Ultimately, in order to limit the deleterious effects of extended defects on 4H-SiC device structures, the formation of these defects must be understood so that a plan for controlling them can be formulated. To this end, we have used site-specific transmission electron microscopy (TEM) 4 in order to analyze 4H-SiC PiN diodes that have been first studied by lightemission imaging (LEI), so that the most interesting regions of the most relevant samples can be chosen.…”