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

Abstract

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.