Impact of the Metal-Gate Material Properties in FinFET (Versus FD-SOI MOSFET) on High-kappa/Metal Gate Work-Function Variation

Abstract

The 3-D technology computer-aided design simulations were performed with four metal-gate materials (i.e., titanium nitride, tungsten nitride, tantalum nitride, and molybdenum nitride) to quantitatively estimate the magnitude of work-function variation (WFV)-induced threshold-voltage variation (WFV-induced sigma-V-TH) in high-x/metal-gate (HK/MG) MOSFETs [e.g., fin-shaped field-effect transistor (FinFET) and fully depleted silicon-oninsulator MOSFETs]. We found that the extended gate area effect in FinFETs extensively varied depending on the gate materials used. In order to substantially suppress the WFV-induced sigma-V-TH in HK/MG complementary metal-oxide-semiconductor technology, a new metal-gate material with the following characteristics should be developed: 1) higher standard deviation of probability for all grains and 2) lower standard deviation of WF values for all grains.