Random Work Function Variation Induced Threshold Voltage Fluctuation in 16-nm Bulk FinFET Devices with High-kappa-Metal-Gate Material

Abstract

The random work-function (WK) induced threshold voltage fluctuation (sigma Vth) in 16-nm TiN metal-gate fin-type field effect transistors (FinFETs) is explored and modeled by using an experimentally validated Monte Carlo simulation approach. The influences of metal-grain size and device geometry aspect ratio on the random WK-induced sigma Vth are studied analytically. The results of this study allow us to identify suitable materials for metal gate and to clarify reduction of the sigma Vth owing to WKF. Among four different gate materials, the titanium nitride possesses the smallest sigma Vth due to small size of metal grains.