Quasi-3D subthreshold current and subthreshold swing models of dual-metal quadruple-gate (DMQG) MOSFETs

Abstract

Quasi-3D models of subthreshold current and subthreshold swing for Dual-Metal Quadruple-Gate (DMQG) MOSFETs are presented in this paper. Equivalent number of gates (ENGs) concept has been utilized to calculate the effective natural length $$\lambda _{DMQG}$$?DMQG of DMQG MOSFETs in spite of solving three-dimensional (3D) Poisson's equation. Further, the effective natural length $$\lambda _{DMQG}$$?DMQG has been used to calculate center channel potential which in turn used to formulate the `virtual cathode' potential equation of the device. Eventually, the subthreshold current modeling is done using Pao-Sah's current equation along with the `virtual cathode' potential equation. Besides, the subthreshold swing model is also derived using `virtual cathode' concept and Boltzmann equation. The effect of different channel length ratios, channel length, oxide thickness and channel thickness of device on the subthreshold current and subthreshold swing of DMQG MOSFETs have been discussed and it is shown that these approximated 3D-model results are in well agreement with the ATLAS simulation results.