Efficient modeling of source/drain tunneling in ultra-scaled transistors

In this work, a comprehensive investigation of the effect of source/drain tunneling in ultra-scaled transistors is presented. A novel approach to efficiently and accurately incorporate the quantum-mechanical effects of source/drain (S/D) tunneling in semi-classical device simulators has been developed. The ballistic quantum transport model has been implemented as part of the Vienna-Schrödinger-Poisson simulation and modeling framework. The transport formalism is based on the quantum transmitting boundary method and has been extended to provide recombination and generation rates of carriers due to the direct tunneling current across the source/drain barrier. The model has been used to investigate the effect of direct S/D tunneling on device performance in ultra-scaled double-gate and nanowire transistors. The variations in transfer and output characteristics due to the tunneling effect have been calculated for different gate lengths and channel widths. The influence on the drain induced barrier lowering is shown.