Correlation of Negative Bias Temperature Instability and Breakdown in HfO2/TiN Gate Stacks

Both negative bias temperature instability (NBTI) and time dependent dielectric breakdown (TDDB) are two major reliability issues for long term performance of high-k gate stacks. In this work, these two degradation mechanisms were extensively analyzed to explore any possible correlation in terms of defects formation. A variety of dielectric stacks were considered to perform NBTI and TDDB. It was observed that NBTI induced defects, generated at the interface and in the interfacial layer were somewhat identical to the defects that dominate the breakdown process.