Numerical investigation of nanoscale SiGe DG MOSFET with graded doping channel for improving reliability behavior

Abstract

The use of lower band gap materials such as SiGe for the DG MOSFET channel is of paramount importance given their compatibility with the process developed for pure Silicon devices. Furthermore, the increased electrons mobility in SiGe material has a positive effect on both drain current and transconductance. However, band gap narrowing due to Ge mole fraction increasing channel is a crucial obstacle that leads to electrical performance degradation. Thus, we present in this paper a novel graded doping channel-based approach to enhance the device reliability. Based on Atlas 2-D simulation of the nanoscale SiGe Double Gate MOSFET including the interface defects near the drain side, we develop numerical models to explain the impact of several doping profile on the immunity performance of the nanoscale transistor against the interface traps density. In this context, subthreshold characteristics of the proposed design (threshold voltage, swing factor and gate current) are investigated and evaluated with respect to the conventional uniform doping profile DG MOSFET characteristics.