H-2-related defects in Si quenched in H-2 gas studied by optical absorption measurements

Optical absorption spectra of Si annealed in H-2 gas followed by quenching were studied. Specimens were high-purity Si (dopant concentration; 4 x 10(1 2) cm(-3)). They were sealed in quartz capsules together with H-2, annealed at high temperatures and quenched in water. Their optical absorption spect ra were measured by an FT-IR spectrometer at about 6 K. Six sharp optical a bsorption peaks were observed at 3618.1, 2131.5, 2062.0, 1838.5, 817.6 and 776.2 cm(-1). The 3618.1 and 1838.5 & 817.6 cm(-1) peaks have been respecti vely assigned to be due to H-2 and H-2*. The activation (or formation) ener gies of H-2 and H-2* were determined from the quenching temperature depende nce of the peak intensities. Those of H-2 (3618 cm(-1) peak) and H-2* (1838 cm(-1) peak) were about 2.2 and 4.8 eV, respectively.