Cointegration of High-Performance Tied-Gate Three-Terminal FinFETs and Variable Threshold-Voltage Independent-Gate Four-Terminal FinFETs With Asymmetric Gate-Oxide Thicknesses

Cointegration of titanium nitride (TiN)-gate high-performance tied-gate three-terminal FinFETs with symmetric gate-oxide thicknesses(t_ ox1 = t_ ox2 = 1.7\ nm)and variable threshold-voltageVₜₕindependent-gate four-terminal (4T) FinFETs with asymmetric gate-oxide thicknesses (t_ ox1 = 1.7\ nmfor the driving-gate-oxide, andt_ ox2 = 3.4\ or\ 7.0\ nmfor the control-gate-oxide) has been successfully developed using conventional reactive sputtering, two-step Si-fin and gate-oxide formation, and resist etch-back processes. A significantly improved subthreshold slope and an extremely lowOFF-state currentIoffare experimentally confirmed in the asymmetric gate-oxide thickness 4T FinFETs by increasing the control-gate-oxide thickness to twice or more the driving-gate-oxide thickness. The developed techniques are attractive for high-performance and low-power FinFET very large-scale integration circuits.