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

Abstract

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