Dual work function phase controlled Ni-FUSI CMOS (NiSi NMOS, Ni{sub}2Si or Ni{sub}31Si{sub}12 PMOS): Manufacturability, Reliability Process Window Improvement by Sacrificial SiGe cap

摘要

This work presents the first comprehensive evaluation of the manufacturability and reliability of dual WF phase controlled Ni-FUSI/HfSiON CMOS (NMOS: NiSi; PMOS: Ni{sub}2Si and Ni{sub}31Si{sub}12 evaluated) for the 45 nm node. RTP1 and poly/spacer height were identified as the most critical process control parameters in our flow. We demonstrate that a novel sacrificial SiGe cap addition to the flow (improved poly-Si/spacer height control) opens the RTP1 process window from ～5°C to ～20°C for gate lengths down to 45nm, making scalable dual WF CMOS Ni-FUSI manufacturable. We demonstrate Vt control with σ～19mV (including wafer to wafer variation, N=1000, 45 nm devices) for NMOS (NiSi), and σ～21mV for PMOS. TDDB and NBTI reliability evaluation of NiSi and, for the first time, of Ni{sub}2Si and Ni{sub}31Si{sub}12 was done. ～1V or larger operating voltages (V{sub}(op)) were extrapolated for a 10 years lifetime. Using a higher back-end thermal budget showed no reliability degradation.