Abstract
To determine the species of point defects which are included in H-point defect complexes in Si, optical absorption spectra of two kinds of electron-irradiated Si doped with H were studied. Specimens were C-doped (carbon concentration: 1.7×1017 cm-3) and high-purity (4×1012 cm-3) Si. They were doped with H by annealing in H2 gas followed by quenching. Then they were irradiated with 3 MV electrons at room temperature. Their optical absorption spectra were measured by an fourier-transform infrared absorption spectroscopy (FT-IR) spectrometer at about 6 K. The intensities of the 1987 and 1990 cm-1 peaks in the C-doped specimen were remarkably weaker than those of the high-purity specimen. This supports the hypothesis that the 1987 and 1990 cm-1 peaks are due to an I·2H (I; self-interstitial) complex, not due to V·2H (V; vacancy) complex since I is known to kick out the substitutional C to interstitial C resulting in a decrease of I concentration in C-doped Si.