The CiCs(SiI)n Defect in Silicon from a Density Functional Theory Perspective.

Carbon constitutes a significant defect in silicon (Si) as it can interact with intrinsic point defects and affect the operation of devices. In heavily irradiated Si containing carbon the initially produced carbon interstitial-carbon substitutional (CiCs) defect can associate with self-interstitials (SiI's) to form, in the course of irradiation, the CiCs(SiI) defect and further form larger complexes namely, CiCs(SiI)n defects, by the sequential trapping of self-interstitials defects. In the present study, we use density functional theory to clarify the structure and energetics of the CiCs(SiI)n defects. We report that the lowest energy CiCs(SiI) and CiCs(SiI)2 defects are strongly bound with -2.77 and -5.30 eV, respectively.