Interstitial Kinetics Near Oxidizing Silicon Interfaces

Accurate modeling of point defect interactions is essential for developing thermal fabrication processes for submicron devices. Recent experimental work on enhanced diffusion during the thermal oxidation of silicon demonstrates that altering generation/recombination processes in the silicon substrate does not affect interstitial supersaturation during oxidation. In contrast, experimental observations of enhanced diffusion during the thermal nitridation of , which results in the growth of a thin interface oxide, indicate that changes within the oxide have a strong influence on interstitial kinetics. These observations suggest that diffusion into the oxide, rather than diffusion into the silicon or surface regrowth, is the dominant sink for interstitials generated by the oxidizing interface. Further, the sublinear dependence of OED and OISF growth on oxidation rate is shown to be a direct result of assuming a steady‐state balance between interstitial generation at the interface and diffusion into the oxide. This work has direct implications to the development of fabrication process simulators in that the oxidation process determines the concentration of interstitials at the interface, rather than the flux of interstitials into the silicon.