Effect of breakdown in ultrathin gate oxides on channel current

Channel current degradation of small MOSFETs after the occurrence of breakdown in ultrathin gate oxides is investigated (Cester et al., 2003). The channel current reduction induced by the breakdown is observed even after eliminating two possible components, i.e., (1) the threshold voltage shift and the mobility degradation due to the interface trap generation, and (2) the flow of the gate leakage current into the drain terminal (Rodriguez et al., 2002). We suppose that the local modulation of the surface potential near the breakdown spot prevents the carrier conduction, and a new model is proposed to interpret the gate width and the gate voltage dependence of the channel current degradation.