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Two dimensional quantum and reliability modelling for lightly doped nanoscale devices

The downscaling of MOSFET devices leads to well-studied short channel effects and more complex quantum mechanical effects. Both quantum and short channel effects not only alter the performance but they also affect the reliability. This continued scaling of the MOS device gate length puts a demand on...

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Main Author: ElKashlan, Rana
Format: Thesis
Published: AUC Knowledge Fountain 2018
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access_status_str Open Access
author ElKashlan, Rana
author_browse ElKashlan, Rana
author_facet ElKashlan, Rana
author_sort ElKashlan, Rana
collection Thesis
dc_rights_str_mv The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.
description The downscaling of MOSFET devices leads to well-studied short channel effects and more complex quantum mechanical effects. Both quantum and short channel effects not only alter the performance but they also affect the reliability. This continued scaling of the MOS device gate length puts a demand on the reduction of the gate oxide thickness and the substrate doping density. Quantum mechanical effects give rise to the quantization of energy in the conduction band, which consequently creates a larger effective bandgap and brings a displacement of the inversion layer charge out of the Si/SiO2 interface. Such a displacement of charge is equivalent to an increase in the effective oxide layer thickness, a growth in the threshold voltage, and a decrease in the current level. Therefore, using the classical analysis approach without including the quantum effects may lead to perceptible errors in the prognosis of the performance of modern deep submicron devices. In this work, compact Verilog-A compatible 2D models including quantum short channel effects and confinement for the potential, threshold voltage, and the carrier charge sheet density for symmetrical lightly doped double-gate MOSFETs are developed. The proposed models are not only applicable to ultra-scaled devices but they have also been derived from analytical 2D Poisson and 1D Schrodinger equations including 2D electrostatics, in order to incorporate quantum mechanical effects. Electron and hole quasi-Fermi potential effects were considered. The models were further enhanced to include negative bias temperature instability (NBTI) in order to assess the reliability of the device. NBTI effects incorporated into the models constitute interface state generation and hole-trapping. The models are continuous and have been verified by comparison with COMSOL and BALMOS numerical simulations for channel lengths down to 7nm; very good agreement within ±5% has been observed for silicon thicknesses ranging from 3nm to 20nm at 1 GHz operation after 10 years.
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id oai:fount.aucegypt.edu:etds-1711
institution American University in Cairo (Egypt)
last_indexed 2026-06-10T12:35:43.583Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from AUC Knowledge Fountain — bepress
publishDate 2018
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spelling oai:fount.aucegypt.edu:etds-1711 Two dimensional quantum and reliability modelling for lightly doped nanoscale devices ElKashlan, Rana The downscaling of MOSFET devices leads to well-studied short channel effects and more complex quantum mechanical effects. Both quantum and short channel effects not only alter the performance but they also affect the reliability. This continued scaling of the MOS device gate length puts a demand on the reduction of the gate oxide thickness and the substrate doping density. Quantum mechanical effects give rise to the quantization of energy in the conduction band, which consequently creates a larger effective bandgap and brings a displacement of the inversion layer charge out of the Si/SiO2 interface. Such a displacement of charge is equivalent to an increase in the effective oxide layer thickness, a growth in the threshold voltage, and a decrease in the current level. Therefore, using the classical analysis approach without including the quantum effects may lead to perceptible errors in the prognosis of the performance of modern deep submicron devices. In this work, compact Verilog-A compatible 2D models including quantum short channel effects and confinement for the potential, threshold voltage, and the carrier charge sheet density for symmetrical lightly doped double-gate MOSFETs are developed. The proposed models are not only applicable to ultra-scaled devices but they have also been derived from analytical 2D Poisson and 1D Schrodinger equations including 2D electrostatics, in order to incorporate quantum mechanical effects. Electron and hole quasi-Fermi potential effects were considered. The models were further enhanced to include negative bias temperature instability (NBTI) in order to assess the reliability of the device. NBTI effects incorporated into the models constitute interface state generation and hole-trapping. The models are continuous and have been verified by comparison with COMSOL and BALMOS numerical simulations for channel lengths down to 7nm; very good agreement within ±5% has been observed for silicon thicknesses ranging from 3nm to 20nm at 1 GHz operation after 10 years. 2018-02-01T08:00:00Z thesis application/pdf https://fount.aucegypt.edu/etds/712 https://fount.aucegypt.edu/context/etds/article/1711/viewcontent/RanaYElKashlan_MSc._20Thesis_20Documentation_FinalVersion_Postdefense_.pdf The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy. Theses and Dissertations AUC Knowledge Fountain Semiconductors Semiconductor Physics
spellingShingle Semiconductors
Semiconductor Physics
ElKashlan, Rana
Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title_full Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title_fullStr Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title_full_unstemmed Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title_short Two dimensional quantum and reliability modelling for lightly doped nanoscale devices
title_sort two dimensional quantum and reliability modelling for lightly doped nanoscale devices
topic Semiconductors
Semiconductor Physics
url https://fount.aucegypt.edu/etds/712
https://fount.aucegypt.edu/context/etds/article/1711/viewcontent/RanaYElKashlan_MSc._20Thesis_20Documentation_FinalVersion_Postdefense_.pdf
work_keys_str_mv AT elkashlanrana twodimensionalquantumandreliabilitymodellingforlightlydopednanoscaledevices