So-called dislocation half-loop arrays in 4H-SiC homo-epilayers were studied by molten KOH etching and atomic force microscopy. It was found that the dislocation half-loops in an array existed at different depths in the epilayer, and they were aligned roughly but not exactly perpendicular to the off-cut direction. These results indicated that the dislocation half-loops in an array were not formed simultaneously, but the array extends by generation of new half-loops during growth. It was also demonstrated that the half-loop arrays could be artificially introduced by creating strain in the material, followed by annealing.

Characteristics of Dislocation Half-Loop Arrays in 4H-SiC Homo-Epilayer. Z.Zhang, R.E.Stahlbush, P.Pirouz, T.S.Sudarshan: Journal of Electronic Materials, 2007, 36[5], 539-42