Annealing behavior of hydrogen-defect complexes in carbon-doped Si quenched in hydrogen atmosphere

Optical absorption spectra and the annealing behavior of hydrogen (H)-point defect complexes in carbon (C)-doped Si after hydrogenation were investigated. Specimens of C-doped Si (C concentration: 1.7×1017 cm−3) were sealed in quartz capsules together with H2 gas and were annealed at a high temperature for 1 h followed by quenching in water. We measured the optical absorption spectra at about 7 K with a Fourier-transform infrared spectrometer. The VH4 (V: monovacancy) defect was almost annealed out at 600 °C. The formation energy of the VH4 defect in C-doped Si was estimated to be about 3.2 eV from the quenching temperature dependence of the 2223 cm−1 peak. The observed 2192 and 2203 cm−1 peaks are probably due to the VH3 defect, which captures one H atom during annealing and become the VH4 defect. After annealing at 700 °C, we observed two absorption peaks at 2093 and 2086 cm−1, which are probably due to Si–H stretching vibration of H on internal surfaces of voids. From these assignments, it was found that V is introduced into C-doped Si at high temperatures, although it is known that C introduces I into Si at high temperatures.