Field and temperature acceleration model for time-dependent dielectric breakdown

Abstract

Electric-field and temperature acceleration models, such as the thermochemical breakdown (linear field dependence) model, the hole-induced breakdown (reciprocal field dependence) model, and the modified hole-induced breakdown model, are discussed. These models are examined; based on the results of long-term time-dependent dielectric breakdown (TDDB) tests over wide ranges of negative gate bias stress (8-13 MV/cm), test temperature (25, 75, and 125/spl deg/C), and oxide thickness (27-181 /spl Aring/). This was accomplished to confirm which model is applicable for thin oxide reliability, and to predict how TDDB in very thin oxide films occurs under a low-field stress for application to future generations of ULSI devices. With respect to the field acceleration dependence of the log-normal intrinsic breakdown at a high temperature of 125/spl deg/C, the thermochemical breakdown (linear field dependence) model yields the best fit when compared with other models, although it is difficult to make exact distinctions from long-term TDDB test results at 25/spl deg/C, even for several months. It is suggested that the thermochemical breakdown model is suitable as a field acceleration model for the TDDB phenomenon. The thermal activation energy and field acceleration parameter, based on the thermochemical breakdown model, exhibit linear dependencies. From the study of oxide thickness dependence between 27 and 181 /spl Aring/, the lifetime and failure rate of intrinsic oxide breakdown can be predicted for a given stress condition.