HKMG process impact on N, P BTI: Role of thermal IL scaling, IL/HK integration and post HK nitridation

Abstract

NBTI and PBTI are studied in IL/HK/MG gate stacks having EOT down to ~ 6Å and fabricated using low T RTP based thermal IL and a novel IL/HK integration. At equivalent EOT, proposed stacks provide improved NBTI and similar PBTI when compared to conventional Chem-Ox IL based HKMG stacks. EOT scaling achieved by RTP thermal IL scaling shows lower rate of increase in NBTI and PBTI when compared to Chem-Ox IL scavenged stacks. Impact of Nitrogen and role of post HK nitridation are studied. Physical mechanism of improved BTI in proposed stacks is discussed in detail.