Effect of fringing capacitances in sub 100 nm MOSFETs with high-K gate dielectrics

Abstract

In this paper we look at the quantitative picture of fringing field effects by use of high-k dielectrics on the 70 nm node CMOS technologies. By using Monte-Carlo based techniques, we extract the degradation in gate-to-channel capacitance and the internal and external fringing capacitance components for varying values of K. The results clearly show the decrease in external fringing capacitance, increase in internal fringing capacitance and a slight decrease in overall capacitance, when the conventional SiO₂ is replaced by high-K dielectric. From the circuit point of view the lower total capacitance will increase the speed of the device, while the internal fringing capacitance will degrade the short-channel performance contributing to higher DIBL and drain leakage.