Oxide Reliability: a new Methodology for Reliability Evaluation at Parametric Testing

Aim of this work is to propose a new fast methodology to be applied to thick gate and tunnel oxides in Flash and embedded Flash processes. Starting from the reliability characterization of the dielectric it is possible to define a very short stress (lower than 1-2sec) which correlates with standard long reliability testing procedures (constant voltage stress, CVS, or constant current stress, CCS). For thick dielectrics, whose significant charge trapping affects the lifetime, the definition of a short stress condition is critical, but it is shown that a short CCS test can overcome this problem. This short test can be introduced at parametric testing in order to screen defective oxides following a criteria directly correlated with device requirements