nMOS Short Channel Device Characteristics After Soft Oxide Breakdown and Implications for Reliability Projections and Circuits

The currents in all N-channel field effect transistor device terminals can be severely degraded when a soft breakdown event occurs from gate-to-drain. These effects become more pronounced for shorter channel lengths. We present a methodology for separating the effects of mobility degradation and threshold voltage shift on post breakdown device characteristics. Using an accurate equivalent circuit model, we analyze the impact of these parameter shifts on post breakdown circuit performance and the implications for post breakdown reliability projections and circuit design.