Gate-First Integration of Tunable Work Function Metal Gates of Different Thicknesses Into High-k/Metal Gates CMOS FinFETs for Multi- VTh Engineering

Gate-first integration of tunable work function metal gates of different thicknesses (3-20 nm) into high-k/metal gates CMOS FinFETs was demonstrated to achieve multiple threshold voltages (V Th ) for 32-nm technology and beyond logic, memory, input/output, and system-on-a-chip applications. The fabricated devices showed excellent short-channel effect immunity (drain-induced barrier lowering ~40 mV/V), nearly symmetric V Th , low T inv (~1.4 nm), and high I on (~780 ¿A/¿m) for N/PMOS without any intentional strain enhancement.