EPR identification of the single-acceptor state of interstitial carbon in silicon

An EPR center labeled Si-L6 is reported which is identified as arising from the singly ionized acceptor state of isolated interstitial carbon (Cᵢ^-) in electron-irradiated crystalline silicon. Correlated deep-level capacitance transient spectroscopy measurements locate the acceptor level at Ec-0.10 eV. The core structure of the defect is a 〈100〉 C-Si interstitialcy similar to that previously proposed for Cᵢ⁺. The spin wave function is substantially more diffuse, however.