Large-Scale Time Characterization and Analysis of PBTI In HFO2/Metal Gate Stacks

Many electrical properties of metal/high-k gate stack are dominated by defects. These defects play an important role in reliability issues in particular positive bias temperature instabilities (PBTI). In this paper, we investigate PBTI with a time resolved measurement technique allowing a large-scale time characterization. This technique allows us to separate different mechanisms, namely fast and slow trapping, newly slow stress-generated traps and finally positive charges. We clearly evidence which of them are or are not activated by temperature. We explain how to take into account these mechanisms for a precise lifetime extrapolation