Statistical Model for Radiation-Induced Wear-Out of Ultra-Thin Gate Oxides after Exposure to Heavy Ion Irradiation

In this work, we present an original model to explain the accelerated wear-out behavior of irradiated ultra-thin oxides. The model uses a statistical approach to the breakdown occurrences based on a nonhomogeneous Poisson process. By means of our model, we can estimate the number and the time evolution of those damaged regions produced by ion hits that generate breakdown spots during high field stresses after irradiation, including the dependence on the oxide field. Also, by using the proposed model, we have studied the wear-out dependence on the stress voltage, gate area, and ion fluence. In particular, by studying the stress voltage dependence of wear-out acceleration, it is feasible to extrapolate the device lifetime even at low operating voltage.