Effect of Ion Energy on Power MOSFET's Oxide Reliability

Heavy ion-induced Power MOSFET's reliability degradation has been studied. Irradiations were realized at low and high energy with the same electronic stopping power at the surface of the die. For both energies, a decrease of the charge to breakdown has been observed after irradiation. However, an enhanced degradation of the oxide layer reliability is observed at low energy. The lifetime reduction at high energy is correlated to local disorder along the ion track that can act as precursor damage. On the other hand, the most important reliability degradation at low energy is attributed to a synergy effect between ionizing and non-ionizing processes. Clusters of defects can indeed be formed, adding an additional wear-out mechanism. These results may be significant in the frame of Single Event Testing