The C_iC_s(Si_I)_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 (C_iC_s) defect can associate with self-interstitials (Si_I's) to form, in the course of irradiation, the C_iC_s(Si_I) defect and further form larger complexes namely, C_iC_s(Si_I)_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 C_iC_s(Si_I)_n defects. We report that the lowest energy C_iC_s(Si_I) and C_iC_s(Si_I)₂ defects are strongly bound with -2.77 and -5.30 eV, respectively.