Interstitial-Carbon Hydrogen Interaction in Silicon

Abstract

The $T$-line luminescence system is created in Si by annealing at 400--600 \ifmmode^\circ\else\textdegree\fi{}C. Shifts and splitting of the spectral features with ${}^{13}\mathrm{C}$ and D isotope substitution identify the presence of two C atoms and one H atom in the center. Uniaxial stress and magnetic field measurements show that the $T$ center has monoclinic $I$ symmetry and possesses an acceptor ( $\ensuremath{-}/0$) level at 0.2 eV below the conduction band. Ab initio cluster calculations lead to a structure in which an interstitial C-H defect binds with a substitutional C atom. The calculated vibrational modes are in good agreement with those observed.