The thermal properties, namely, the thermal stability and the activation en
ergy, of H-point defect complexes in Si were investigated. Specimens were d
oped with H by annealing in H-2 gas followed by quenching. Then, they were
irradiated by 3 MV electrons at room temperature. Subsequently, they were a
nnealed isochronally or isothermally. Optical absorption spectra of H-point
defect complexes were measured at 7 K. Due to isochronal annealing, the 21
22, 1838, and 817 cm(-1) peaks disappeared below 200 degrees C. On the othe
r hand, 2223 and 2166 cm(-1) peaks formed at above 125 and 175 degrees C, r
espectively. From isothermal annealing experiments, the binding energies of
H-2* (1838 cm(-1) peak) and I (I: a self-interstitial) H-2 or V (V: a vaca
ncy) H-2 (1987 and 1990 cm(-1) peaks) were determined to be about 1.5 and 2
.0 eV, respectively. The generation of the 2223 cm(-1) peak was due to reac
tion between H-2 and the 2122 cm(-1) defect. (C) 1999 American Institute of
Physics. [S0021- 8979(99)02721-8].