Impact of charge trapping on the voltage acceleration of TDDB in metal gate/high-k n-channel MOSFETs

The root cause for the increase in the TDDB voltage acceleration with decreasing stress voltage in metal gate/high-k n-channel FETs is investigated. Using DC and AC stress methodologies, the effect could be linked to charge trapping in the high-k gate dielectric. Furthermore, a correction for charge trapping is proposed, which results in a single power law voltage dependence for all stress conditions.