Design and Simulation of Nano Scale High-K Based MOSFETs with Poly Silicon and Metal Gate Electrodes

High-k / Metal gate technology is emerging as a strong alternative for replacing the conventional oxynitride dielectrics and polysilicon gates in scaled MOSFETs for both high performance and low power applications. The key issues which complicates the use of high-k materials such as reduction in drain current, transconductance and mobility are resolved by replacing polysilicon by thermally stable, low work function metal gate. The advantages of using high-k over conventional SiO2 dielectrics and metal gate over poly gate are compared. The simulation results show the reduction of gate leakage current by six orders of magnitude for HfO2 – TiN structures compared to SiO2 – polysilicon structures. Similarly the subthreshold swing (1/S) is also found to decrease from 90.5mV/decade (for conventional SiO2 structure) to 74.6mV/decade for high-k metal gate structure.