PBTI-associated high-temperature hot carrier degradation of nMOSFETs with metal-gate/high-k dielectrics

Due to the increased physical dielectric thickness and reduced gate leakage in metal-gate/high-k devices, degradation caused by channel hot carriers (HCs) becomes more significant than positive bias temperature stress. In an analysis of metal-gate/high-k devices, accelerated channel HCs were found to induce permanent interface damage. Moreover, the overall threshold voltage shifts caused by HC stress were enhanced at higher temperatures, which is due to an association with positive bias temperature instability. Therefore, high-temperature HC stress has emerged as a dominant degradation factor in short-channel nMOSFETs with metal-gate/high-k dielectrics.