Connection structures between type - I and type - II defects in neutron irradiated - Si 3 N 4

High-resolution electron microscopy (HREM) observation clarified that various types of interstitial dislocations were induced into -Si 3 N 4 by highdose neutron irradiation, and two of them have been analysed and reported in our previous papers. These two defective structures are called type-I and type-II. They are interstitial dislocation loops introduced into {100} and {110} planes, respectively. In this study, it was found that some of these dislocation loops connected with each other. The connections of type-I-L2 type-II-B and type-I-R2 type-II-A dislocations were observed by HREM. Tetrahedral arrangements of the connected parts are proposed, based on the simplified crystal structure model of -Si 3 N 4 . In addition, a new type of defect, type-III, was found. Type-III is an interstitial dislocation loop introduced into {100} planes. It was also found that type-I-A and type-III dislocations connected with each other. ..................................................................................................................................................................................................................