A systematic investigation of the influence of processing parameters on the radiation hardness of reoxidized nitrided oxides

Abstract

To optimize radiation hardness of reoxidized nitrided oxides (RNO) gate dielectrics the influence of processing parameters was systematically investigated. The dependence on oxidation temperature, nitridation temperature and time, and reoxidation temperature and time was determined by means of orthogonal matrices. The best samples exhibited a 30 times lower flatband voltage shift than the worst. Compared to hardened gate oxides optimized RNO dielectrics showed an improvement in radiation hardness by a factor of 7. At 1.5 Mrad(Si) the flatband voltage shift of 25 nm gate dielectrics was reduced to 150 mV.