Hydrogen-point defect complexes in electron-irradiated C-doped and high purity Si

To determine the species of point defects which are included In H-point def ect complexes in Si, optical absorption spectra of two kinds of electron-ir radiated Si doped with H were studied. Specimens were C-doped (carbon conce ntration: 1.7 x 10(17) cm(-3).) and high-purity (4 x 10(12) cm(-3)) Si. The y were doped with H by annealing in H-2 gas followed by quenching. Then the y were irradiated with 3 MV electrons at room temperature. Their optical ab sorption 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 19 87 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 subs titutional C to interstitial C resulting in a decrease of I concentration i n C-doped Si.