TEMPERATURE AND ELECTRIC-FIELD CHARACTERISTICS OF TIME-DEPENDENT DIELECTRIC-BREAKDOWN FOR SILICON DIOXIDE AND REOXIDIZED-NITRIDED OXIDES

TDDB characteristics of 150 Angstrom reoxidized nitrided oxide (ONO) g ate dielectrics were examined at temperatures from 77K to 400 K. These ONO films were processed with different conditions of rapid thermal n itridation (RTN) and rapid thermal re-oxidation (RTO). Optimized ONO f ilms show better Q(bd) performance while maintaining a similar tempera ture and electric field dependence compared to SiO2. The low temperatu re activation energy for ONO and SiO2 is found to be strongly temperat ure dependent, and the charge to breakdown, Q(bd), is closely related to the electron trap generation/trapping rate rather than the amount o f hole trapping for high held stress. To further verify the effect of hole trapping on TDDB, X-ray irradiation was applied to wafers at diff erent process steps. The results clearly show that the amount of hole trapping does not correlate with the charge to breakdown.