Analytical modeling of subthreshold characteristics by considering quantum confinement effects in ultrathin dual-metal quadruple gate (DMQG) MOSFETs

In this work, analytical models of subthreshold characteristics for an ultrathin dual-metal quadruple gate MOSFET have been developed by considering the quantum confinement effects. The 2D Schrödinger's equation has been solved analytically to obtain the threshold voltage and subthreshold current of ultrathin dual-metal quadruple gate MOSFET with minimum cross-section of 3nm×3nm. The inversion charge density at the threshold condition is obtained by considering minimum sub-band energy levels with a square potential well approximation for a two dimensional (width and height) carrier confinement. The subthreshold characteristics have been analyzed by varying different device parameters like channel cross-section, gate length ratio, gate metal work functions and gate oxide thickness. Further, the effect of 2D charge carrier confinement on drain induced barrier lowering (DIBL) has also been discussed using the threshold voltage model. The proposed models are validated against the numerical simulation results obtained from 3D ATLAS device simulator.