Ultra-thin re-oxidized nitrided-oxides prepared by rapid thermal processing

We applied, for the first time, rapid thermal processing to the full fabrication process of ultrathin reoxidized nitrided-oxides. 8-nm-thick oxides nitrided at 950 and 1150°C for 60 s were re-oxidized in O2at 900- 1150°C for 15-200 s. We studied how nitridation and reoxidation conditions affect the electrical characteristics of the dielectrics, especially, the charge-trapping properties: charge-to-breakdown QBD, flatband voltage shift ΔVFB, and increase of midgap interface state density ΔDit_munder high-field stress. Both ΔVFBand ΔDit_mreduce as re-oxidation proceeds in the present experimental conditions. Rapid re-oxidation, in a precisely controlled manner, achieves striking improvement of dielectric integrity: the QBDis increased by about 16 times and both the ΔVFBand ΔDit_mare reduced by more than 2 orders of magnitude compared with those of oxides, while maintaining the low initial VFBand Dit_mcomparable to those of oxides.