Effect of size quantization and quantum capacitance on the threshold voltage of a 2D nanoscale dual gate MOSFET

Abstract

The size quantization effect in the channel of a 2D nanoscale MOSFET is studied using a self-consistent quantum method. Under this, Schrodinger-Poisson equations are solved for determining the electron density for 2D device channels from 3 nm × 3 nm to 100 nm × 100 nm. The lower dimension channels show a peak of the electron density at the middle whereas higher dimension channels show the accumulation of the electrons at the oxide/semiconductor interface. Also, the role of quantum capacitance on the threshold voltages of these nanoscale devices is investigated as a function of channel dimensions and electron effective masses. It is observed that not only the size but the electron effective masses dominate the conductivity of the channel for such nanoscale devices. Here, the channel electron densities are obtained using density matrix formalism. A block diagonal Hamiltonian Matrix [H] is constructed for this oxide/channel/oxide 2D structure and the channel is discretized by using the finite-difference method. This analysis is important for understanding the physics of the size quantization and its effect on the threshold voltage.