Post-soft-breakdown characteristics of deep submicron NMOSFETs with ultrathin gate oxide

The impacts of soft-breakdown (SBD) on the characteristics of deep sub-micron NMOSFETs were investigated. It is shown that the BD location plays a crucial role in the post-BD switching function of the device. When BD occurs at the channel, the turn-on behavior of the drain current would not be significantly affected, which is in strong contrast to the case of ED at the drain, Nevertheless, significant increase in gate current is observed in the off-state when the gate voltage is more negative than -1 V. Its origin is identified to be due to the action of two parasitic bipolar transistors formed after SBD occurrence at the channel.