Investigation of impact of gate underlap/overlap on the analog/RF performance of composite channel double gate MOSFETs

Abstract

The influence of gate overlap and underlap on the DC/RF behavior of a composite channel based double gate MOSFET (DG MOSFET) that can be used for RF/analog applications is investigated using the 2D Sentaurus TCAD tool in this work. An InAs-inserted In07Ga0.3As composite channel, double silicon delta doping technology, n+-In0.53Ga0.47As source and drain regions, and Si3N4 passivation are some of the key features of the proposed device. 2D-Sentaurus Technology Computer Aided Design (TCAD) simulation has been performed using the hydrodynamic model. Interface trap models have also been incorporated to increase the accuracy of TCAD simulations carried out at room temperature. Key RF/analog figures of merit such as drain current (ID), transconductance (gm), gate leakage current (IGS), subthreshold current, drain induced barrier lowering, electron velocity in the quantum well, cutoff frequency (fT), and maximum oscillation frequency (fmax) have been explored to analyze the RF/analog performance of the proposed device. TCAD simulations reveal the fact that reducing the gate length and employing a gate underlap strategy can improve the analog and RF performance of the proposed DG MOSFET.