Single Shockley stacking fault expansion from immobile basal plane dislocations in 4H-SiC

Abstract

Some combinations of immobile partial dislocations (PDs) that constitute basal plane dislocations (BPDs) have not previously been considered as sources for single Shockley stacking fault expansion. We searched for and found this type of BPD and investigated its structure. The realistic reason for immobile C-core PDs being converted into mobile Si-core PDs is speculated from the results obtained by plan-view transmission electron microscopy (TEM) and cross-sectional scanning TEM. A model is proposed from a dynamic viewpoint for interpreting the mechanism of core-species change by step-flow motion during epitaxial crystal growth in 4H-SiC. Moreover, all possible combinations of immobile PDs are summarized and the necessary condition for immobile BPDs to change to include mobile PDs is discussed.

Effect of basal plane dislocation structures on single Shockley-type stacking fault expansion rate in 4H-SiC

“…[24][25][26][27] The Burgers vectors and line directions of the PDs in various 1SSF shapes have been characterized using photoluminescence (PL) and transmission electron microscopy (TEM) analyses, and the results can explain the expanded 1SSF shapes by the combinations of the Burgers vector and line direction of the BPD at the origin. [21][22][23][26][27][28][29][30][31][32][33] 1SSF shapes are understood by the different expansion rates of leading PDs of 30°or 90°Si(g); namely, 90°S i(g) PDs expand faster than 30°Si(g) PDs. 34,35) Only a few experiments on the expansion rates of 1SSFs have been reported, and these were conducted by electroluminescence (EL) or UV illumination.…”

Structural study of single Shockley stacking faults terminated near substrate/epilayer interface in 4H-SiC

“…28) Although the expansion and contraction phenomena of 1SSFs have been closely examined experimentally, [29][30][31][32][33] analytically, [34][35][36] and theoretically, 37,38) the structure of the PDs that constitute the 1SSFs has not yet been fully elucidated or demonstrated experimentally, particularly in real power devices such as PiN diodes. [39][40][41][42][43] In many experimental observations, 1SSFs start expanding from the substrate/epilayer interface side toward the epilayer surface and terminate in the p-anode layer when forward bias is applied to a PiN diode. 39) In this case, the terminated part of the 1SSF was a straight line along [1 ¯100] direction observed by photoluminescence (PL) imaging, but was revealed to be a zigzag line by transmission electron microscope (TEM) observation.…”

“…In contrast, 1SSF expansion from the epilayer surface to deeper regions has been considered possible by the different combinations of Burgers vectors and the dislocation line directions of the BPDs. 42) Electroluminescence (EL) and PL imaging experiments suggest that this type of 1SSF terminates near the substrate/epilayer interface. 44) However, the detailed structure in the deepest part of the epilayer remained unclear.…”

Partial dislocation structures at expansion terminating areas of bar-shaped single Shockley-type stacking faults and basal plane dislocations at the origin in 4H-SiC

“…Since we believe that structural elucidation is essential for understanding and controlling this issue, we have previously investigated the detailed structure of triangular 1SSFs in which the right-angle is at the shallower side in the epilayer using photoluminescence (PL) and transmission electron microscope (TEM) analysis. [18][19][20][21][22] In addition, a triangular 1SSF with the right-angle at the deeper side in the epilayer was also examined, 23,24) with the BPD at the origin found to have converted from a threading edge dislocation (TED) at a relatively shallow region of the epilayer (1.6 μm deep from the surface) with the converted BPD then changing direction toward the surface at around 1.5 μm deep. 23) This configuration from a deep TED to a shallow TED via a BPD is referred to as "TED-BPD-TED."…”