A new SiO2growth by Fluorine-enhanced thermal oxidation

A new low-temperature oxidation technique for silicon to obtain a high quality Si-SiO2interface is developed. A few tens nanometer thick oxide layer can be grown for 30 min at temperatures between 600 and 800°C by adding a few hundred ppm NF3gas into a dry oxygen atmosphere. Fluorine atoms incorporated in the oxide layer are substituted by oxygen atoms through post-annealing in pure oxygen gas at the same temperature as oxidation. The interface state density is as low as 2×10¹⁰cm^-2eV^-1near midgap for oxide grown at 800 °C and is 8×10¹⁰cm^-2eV^-1even for oxide at 600°C.