Analysis of charge trapping and breakdown mechanism in high-k dielectrics with metal gate electrode using carrier separation

Abstract

Using the carrier separation measurement technique, we are able to distinguish two different breakdown mechanisms: a high-k bulk initiated, and an interfacial layer initiated. The results correlate with the statistical Weibull distribution showing a polarity dependent breakdown in high-k stacks. A model of charge trapping at different spatial locations in HfAlO/sub x/ with a TaN gate structure is proposed to explain the polarity dependence of charge trapping characteristics and breakdown mechanisms.