2D Quantum Mechanical Simulation of Gate-Leakage Current in Double-Gate n-MOSFETs

Abstract

The direct gate leakage current in double-gate ntype MOSFETs with physical gate lengths of 10 nm is investigated. This work uses a combination of a two-dimensional non-equilibrium Green's function (NEGF) based upon a realspace expansion method and Poisson's equation, which are solved self-consistently. In the conventional 1D analysis of the gate leakage current, an optical potential or an imaginary energy has been necessary to broaden the energy level in the triangular quantum well for reduction of computational costs. It is found that, however, different from the results in the conventional 1D analysis, peaks in the current density energy spectra, equivalently the energy levels, are broadened even under zero drain bias condition due to the quantum mechanical scatterings in the presence of the source and drain electrodes. This fact proves that the optical potential used in the conventional 1D simulation merely models the effect of the existence of the electrodes and the 2D analysis gives more sound results.

Hole Transport Mechanism in Silicon and Germanium Nanowire Field Effect Transistors

“…We calculate the hole current by the NEGF method. [8][9][10][11][12] In the present study, we neglect scattering and assume ballistic transport. The potential profiles are obtained through a self-consistent solution of three-dimensional Poisson and NEGF equations.…”

“…7) As a result, drift diffusion and Monte Carlo simulations lose predictive capability. Nonequilibrium Green's function (NEGF) method [8][9][10][11][12] allows one to perform quantum transport simulation in ultrasmall MOSFETs. By combining the NEGF method with an empirical tightbinding approximation (TBA), 13,14) quantum-mechanical computations including full-band structures can be achieved.…”