The morphologies and nucleation sites of stacking faults, formed during the forward operation of 4H-type p-i-n diodes were investigated by using optical emission microscopy and transmission electron microscopy. The partial dislocations which bounded the stacking faults were mainly aligned with <11▪0> directions, with Burgers vectors of 1/3<1¯1▪0> type. Arrays of dislocation half-loops in the blocking layer served as nucleation sites for double-rhombic stacking faults. The morphology of these stacking faults indicated that short basal plane segments associated with threading dislocations were the origin of rhombic stacking faults. All of the dislocations in a half-loop array had the same Burgers vector, and nucleated on a single basal plane; as evidenced by the merging of double-rhombic stacking faults. Most pre-existing basal-plane dislocations within the blocking layer, which were visible in optical emission microscopic images, dissociated to form stacking faults during degradation. Basal-plane dislocations aligned along the off-cut direction formed rectangular stacking faults, while others broke up into partial dislocation segments, along <11▪0> directions, which were often wedge-shaped. Thus, all of the nucleation sites of stacking faults corresponded to pre-existing dislocation segments residing on basal planes. The morphology and evolution of double-rhombic stacking faults indicated that p-i-n diode degradation could not be driven by stresses in the structure.

Nucleation Sites of Recombination-Enhanced Stacking Fault Formation in Silicon Carbide p-i-n Diodes. S.Ha, M.Skowronski, H.Lendenmann: Journal of Applied Physics, 2004, 96[1], 393-8