Observation of switching behaviors in post-breakdown conduction in NiSi-gated stacks

Abstract

For NiSi FUSI gate transistors, switching behaviors have been observed after breakdown (BD) under certain favorable conditions. The conductive BD path can be ¿switched-off¿ if a reverse bias, as opposed to the stressing voltage, is applied, a condition required for observing SET and RESET conduction in switching material systems. Using the percolation model of BD of gate dielectric systems, we explain this switching behavior as a result of passivation of oxygen-deficient BD path. First ionized oxygen atoms are removed from the BD path upon BD, and are driven by e-field and ¿stored¿ in the NiSi gate. Then, upon applying a threshold reverse bias, they are driven back to the nanoscale BD path and due to the presence of a Joule heating in the highly resistive BD path, they rebond/passivate the Si dangling bonds in the oxygen-deficient BD path. This means that BD transistor can be ¿repaired¿ electrically by a reverse threshold voltage to expend its lifetime.