Deep level transient spectroscopy measurements were performed to investigate deep levels in epitaxially grown n-type Si layers introduced by high-energy He2+ irradiation and subsequent annealing at various temperatures. Three deep levels (D1: 0.46–0.49 eV; D2: 0.52 eV; D3: 0.64 eV) were found to be generated near the mid-gap level after post-annealing at temperatures of 300–450 C. The generation behavior of these deep levels was in reasonable agreement with the annihilation of divacancies. Therefore these energy levels were associated with high-order vacancy clusters which were formed by combination of some vacancies during the anneal-out of divacancies, and were attributed to various dangling-bonds like electronic states presenting on the internal surfaces of the clusters.

Deep Level Centers in Silicon Introduced by High-Energy He Irradiation and Subsequent Annealing. Y.Nakano, M.Ishiko, H.Tadano: Journal of Vacuum Science and Technology B, 2002, 20[1], 379-81