Fluorine-enhanced thermal oxidation of silicon in the presence of NF3

The oxidation rate of silicon has been dramatically increased at temperatures between 600 and 800 °C by adding NF3 gas to a dry oxygen atmosphere. The chemical analysis of the resulting oxide has revealed that fluorine atoms in SiO2 are incorporated as Si–F bonds. The existence of such bonded-fluorine atoms enhances the diffusion of oxidant through the oxide layer. The oxidation reaction rate in the SiO2-Si interface is also remarkably increased because fluorine atoms in the interface create silicon dangling bonds and weakly positively charged silicon atoms as well. The kinetics of the fluorine-enhanced oxidation has primarily been interpreted in terms of the Deal–Grove model.