Formation and annihilation of H-point defect complexes in quenched Si doped with C

We investigated the formation and annihilation of H-point defect complexes formed in C-doped Si by heating at high temperatures followed by quenching in hydrogen gas. Specimens of C-doped Si were sealed in quartz capsules tog ether with hydrogen (H) gas, at pressure 0.8-1.5 atm at high temperature, a nd were heated at high temperature for 1 h followed by quenching in water. We measured their optical absorption spectra at about 7 K with an Fourier t ransform infrared spectrometer. We observed several optical absorption peak s due to H-point defect complexes. The optical absorption peaks observed at 2192 and 2203 cm-1 were assigned to the Si-H stretching mode of three hydr ogen atoms bound to a vacancy (VH3 defect). The formation of the VH4 defect is due to the reaction between H and the VH3 defect. From isothermal annea ling experiments, the activation energy for the dissociation of the VH4 def ect was determined to be about 2.5 eV. (C) 2000 American Institute of Physi cs. [S0021-8979(00)04021-4].