A New Two-Dimensional Analytical Model for Nanoscale Symmetrical Tri-Material Gate Stack Double Gate Metal–Oxide–Semiconductor Field Effect Transistors

Abstract

Based on the resultant solution of two-dimensional (2D) Poisson's equation in silicon region, a new, compact and analytical model for nanoscale fully depleted, symmetrical tri-material gate stack double-gate (STMGSDG) metal–oxide–semiconductor field-effect transistor (MOSFET) has been developed. The STMGSDG MOSFET exhibits significantly reduced short-channel effects (SCEs) when compared with the symmetrical single-material gate stack double-gate (SSMGSDG) MOSFET. It is found that the threshold voltage roll-off for the fully depleted STMGSDG MOSFET can be effectively reduced by using both thin Si film and thin gate oxide. Besides, the high ratio of large work function of metal gate 1 (L1) to the total gate can efficiently suppress the drain-induced barrier lowering (DIBL) and maintain the low threshold voltage degradation. This study not only presents a precise 2D analytical model of the surface potential and threshold voltage, but also discusses the electric field distribution in the channel region, subthreshold swing and subthreshold current for the STMGSDG MOSFET. The new model is verified to be in a good agreement with numerical simulation results over a wide range of the device parameters.