Nature of breakdown in ultrathin gate dielectrics

Post-breakdown reliability forms an important aspect of ultrathin gate dielectric lifetime projection in state-of-the-art MOSFET. In particular, digital breakdown plays a predominant role in the early stage of the dielectric breakdown. In this paper, we review the importance of digital breakdown in SiON gate dielectrics of less than 2.5 nm, the possible underlying mechanism(s) and its impact on the post-BD lifetime projection of a device operating at nominal voltages.