Quantitative Measurement of Interstitial Flux and Surface Super-saturation during Oxidation of Silicon

During the oxidation of silicon, interstitials are generated at the oxidizing surface and diffuse into the silicon. Boron diffusion was used to map the local interstitial super-saturation, the ratio of interstitial concentration to the equilibrium concentration of interstitials I/I, versus depth above buried Si0.795Ge0.2C0.005 layers during oxidation. The average interstitial supersaturation at the silicon surface, extrapolated from the depth profiles, is measured as, ~24 and ~11.5 for 750°C and 850°C respectively. Using the measured interstitial concentration at the surface, the silicon interstitial injection into the silicon is calculated for oxidation at 750°C and 850°C. Finally, it is found that the surface boundary condition remains fixed over an interstitial injection rate ranging over 4 orders of magnitude.