Investigation of transport, capacitance, and high-accuracy modeling aspects in low-dimensional devices for tunneling applications
In this work an experimental study has been set out to quantify the impact of quantum confinement effects on the total gate capacitance of low-dimensional (1D and 2D) Field-Effect-Transistors (FETs). Sophisticated measurements of ultra-small capacitances led to the experimental demonstration of: 1) first direct observation of the 1D density-of-states in Silicon nanowires, and 2) measurement of the exchange-correlation capacitance as manifestation of electron-electron interactions in 2D semiconductor MOSFETs. Furthermore, it is discussed and quantitatively shown how these phenomena may impact the on-state performance of Tunneling-FETs (TFETs) as the total gate capacitance is altered by the quantum confinement effects. Due to the increasing need of modeling accurately the performance of aggressively scaled-down TFETs, a new compact model to simulate current-voltage characteristics in TFETs is presented. The development of this model provides deep insight into how to describe properly tunneling phenomena in TFETs. It is shown that the results of the proposed model are in excellent agreement with the results obtained through rigorous numerical simulations using the non-equilibrium Green’s function (NEGF) formalism.
Appenzeller, Purdue University.
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