Electron paramagnetic resonance of multistable interstitial-carbon–substitutional-group-V-atom pairs in silicon

A total of five new electron paramagnetic resonance (EPR) centers are observed in electron-irradiated P-, As-, and Sb-doped silicon. Three are identified as arising from the neutral charge state of the stable configuration and two of the four metastable configurations of an interstitial-carbon–substitutional-phosphorus (${\mathrm{C}}_{\mathit{i}}$-${\mathrm{P}}_{\mathit{s}}$) pair, recently discovered by deep level transient capacitance spectroscopy. The other two are identified as arising from the corresponding stable configurations of ${\mathrm{C}}_{\mathit{i}}$-${\mathrm{As}}_{\mathit{s}}$ and ${\mathrm{C}}_{\mathit{i}}$-${\mathrm{Sb}}_{\mathit{s}}$ pairs. Combining unusual uniaxial-stress-alignment results with analysis of the EPR spectra allows detailed models to be proposed for the different defect configurations and for the mechanism of conversion between them. We conclude that the stable state consists of a 〈100〉-split-C–group-V-atom interstitialcy which converts under electronic excitation to the metastable configurations by ejecting the carbon backward toward the nearest ${\mathit{T}}_{\mathit{d}}$ interstitial site from which it forms similar C-Si interstitialcies with its surrounding Si atoms.