Temperature-dependent retardation effect of dopants on oxygen diffusion in heavily doped Czochralski silicon

The influence of boron (B), arsenic (As), and antimony (Sb) on oxygen diffusivity at 500-800 degrees C was investigated in heavily doped Czochralski silicon wafers with resistivities below 0.02 Ohm cm. The oxygen diffusivity was determined from the outdiffusion profile measured by secondary ion mass spectrometry after prolonged heat treatments. It was found that the heavily doped As and Sb reduce the oxygen diffusivity more at lower temperature. The increases in the activation energy for diffusion were found to be about 0.64-0.68 and 1.40 eV for As and Sb doping, respectively. Heavy B doping, however, exhibited anomalous temperature dependence showing a reduction rate peak around 600-700 degrees C, supposedly due to enhanced formation of immobile oxygen aggregates. (C) 2000 American Institute of Physics. [S0003-6951(00)00629-X].