Kinetic study of oxygen dimer and thermal donor formation in silicon

Computer simulations of the generation kinetics of thermal double donors (T DD's) in Czochralski-grown silicon have been performed and compared with ex perimental data for samples heat treated at temperatures between 350 and 42 0 degrees C for durations up to 500 h. The experimental data were obtained by Fourier-transform infrared spectroscopy exploring the recent finding tha t local vibrational modes can be associated with the individual TDD's. A mo del assuming sequential generation of the TDD's and a fast diffusing oxygen dimer has been found to quantitatively reproduce the experimental data. Th e diffusivity of the oxygen dimer was estimated to be similar to 10(6) time s the value of interstitial oxygen at 400 degrees C, with an activation ene rgy of similar to 1.3 eV and a preexponential factor of similar to 3 x 10(- 4) cm(2) s(-1). The transformation from TDD1 to TDD2 is well described by a first-order reaction having an activation energy of similar to 2.5 eV, str ongly indicating that the process involves motion of interstitial oxygen at oms (O-i). This conclusion is further supported by the deduced value for th e preexponential factor, being very close to that for the jump frequency of O-i. [S0163-1829(98)04843-7].