H2-related defects in Si quenched in H2 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(12) cm(-3)). They were sealed in quartz capsules together with H-2, annealed at high temperatures and quenched in water. Their optical absorption spectra were measured by an FT-IR spectrometer at about 6 K. Six sharp optical absorption 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 respectively assigned to be due to H-2 and H-2*. The activation (or formation) energies of H-2 and H-2* were determined from the quenching temperature dependence 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.