Optical absorption due to H-point defect complexes in quenched Si doped with C

摘要

We investigated the point defects, which exist at high temperatures in C-doped Si. Specimens were prepared from a floating-zone grown Si crystal doped with C (C concentration: 1.7 X 10~(17) cm~(-3)). They were sealed in quartz capsules together with hydrogen (H) gas, with pressure of 1 or 0.8 atm at high temperature, and were annealed at high temperature for 1 h followed by quenching in water. We measured their optical absorption spectra at about 7 K with an FT-IR spectrometer. Several peaks coincided with those observed in proton-implanted Si. We concluded that H-point defect complexes exist in those speciments. In C-doped Si, VH_4 (V: monovacancy) defects are formed by the reaction between VH_3 defect and H during quenching or annealing. The formation energy of V obtained in this study is smaller than the calculated one in intrinsic Si crystal by more than 1.5 eV.