The structures, sizes and distributions of secondary defects in high-energy B+- or Al+-implanted 4H-type material were investigated by means of cross-sectional transmission electron microscopy and secondary ion mass spectrometry. Three types of defect structure were detected. The first (type-I) was an extrinsic Frank partial dislocation loop which was parallel to {00•1} and was the same as that observed in keV-energy B+- or Al+-implanted material. The second (type-II) was another extrinsic dislocation loop, with an extra Si-C bilayer parallel to {00•1}. It had not been previously reported. The final type (type-III) had no extra Si-C bilayer. The defect-type was related to size. When the latter was greater than about 12nm, the defect became type-I or type-II and the defects which were smaller than about 12nm were type-III. The range of secondary defect sizes depended upon the implanted ion-type and dose. The maximum size of the defects increased with dopant concentration, and that in B+-implanted samples was greater than that in Al+-implanted ones for a given volume dopant concentration. The minimum size of the defects seemed to be independent of the dopant concentration and ion species. It was equal to 2 to 4nm in any case. These defects were distributed within the deeper regions of the projected range after low-dose implantation. On the other hand, they extended from near to the surface in high-dose implanted samples.

Structure and Distribution of Secondary Defects in High Energy Ion-Implanted 4H-SiC. T.Ohno, N.Kobayashi: Journal of Applied Physics, 2001, 89[2], 933-41