Effects of N-Rich TiN Capping Layer on Reliability in Gate-Last High-k/Metal Gate MOSFETs

Time-dependent dielectric breakdown (TDDB) and bias temperature instability (BTI) in gate-last technology are studied to characterize the gate-last HK/MG MOSFETs with enrichment of nitrogen inside HK/MG stack and its effects. Especially, to prevent Nitrogen-induced defect generation leading to extra NBTI degradation, it is needed that nitrogen should be mainly inside bulk HfO 2 while interface layer (IL) is free from the effect of nitrogen. To explore this, N-rich TiN capping layer deposition and plasma nitridation (PN) approaches are introduced and compared.