INTERACTIONS OF SILICON POINT-DEFECTS WITH SIO2-FILMS

Interactions of point defects with SiO2 films play a central role in integrated circuit fabrication processes. In this work, a model is developed for the Si-SiO2 system that considers the segregation of excess silicon between the oxide and the silicon substrate and diffusion and reaction of that excess silicon in SiO2. The model is able to explain a broad range of experimental observations under both oxidizing and nonoxidizing conditions in a consistent manner including: the variation of interstitial supersaturation with oxidation rate in steam and dry O2 ambients, oxidation enhanced and retarded diffusion results in <100> and <111> silicon, the large interstitial supersaturation resulting from the nitridation of SiO2, the reduction of SiO2 in argon and the corresponding decrease in interstitial concentration, contradictory calculations of effective interstitial diffusivity, and the greatly reduced effective recombination velocities for nitrided oxides relative to capped oxides.