Fundamental aspects of HfO ₂-based high-k metal gate stack reliability and implications on t _inv-scaling

Experimental reliability trends indicate that t inv-scaling with HKMG stacks remains challenging because NBTI, PBTI and TDDB reliability margins rapidly decrease with decreasing t inv values and increasing gate leakage current. A case is made that these observed trends arise from the layer structure and the materials properties of the SiO(N)/HfO 2 dual dielectric. Therefore, fundamental reliability limitations appear to increasingly impact HKMG stack scaling. © 2011 IEEE.