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2D Quantum Transport Modeling in Nanoscale MOSFETsWith the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density- gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions, oxide tunneling and phase-breaking scattering are treated on equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. Quantum simulations are focused on MIT 25, 50 and 90 nm "well- tempered" MOSFETs and compared to classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. These results are quantitatively consistent with I D Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and sub-threshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.
Document ID
20010117313
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Svizhenko, Alexei
(NASA Ames Research Center Moffett Field, CA United States)
Anantram, M. P.
(NASA Ames Research Center Moffett Field, CA United States)
Govindan, T. R.
(NASA Ames Research Center Moffett Field, CA United States)
Biegel, Bryan
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Electronics And Electrical Engineering
Funding Number(s)
PROJECT: RTOP 519-40-12
CONTRACT_GRANT: NCC2-5304
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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