The Impact of High-K Gate Dielectrics on Sub 100 nm CMOS Circuit Performance

Abstract

The potential impact of high permittivity gate dielectrics on the circuit performance is studied over a wide range of gate dielectrics using 2-Dimensional device and monte-carlo simulations. It is found that there is a decrease in parasitic outer fringe capacitance, gate to channel capacitance and an increase in internal fringe capacitance, when the conventional silicon dioxide is replaced by high-K gate dielectrics. The lower parasitic outer fringe capacitance is beneficial in reducing the circuit delay, while an increase in internal fringe capacitance and decrease in gate to channel capacitance will degrade the gain, power dissipation and noise margin of the circuit. Also, from the circuit point of view, at the 70nm technology generation, the presence of an optimum Kgate for different subthreshold leakage currents has been identified