Abstract

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.

Department

Electronics & Communications Engineering Department

Degree Name

MS in Electronics & Communication Engineering

Graduation Date

2-1-2018

Submission Date

August 2017

First Advisor

Ismail, Yehea

Committee Member 1

Anis, Mohab

Committee Member 2

ElMoursy, Magdy

Extent

69 p.

Document Type

Master's Thesis

Rights

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.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

This thesis would not have been completed without the help of several people. I cannot express enough my deepest gratitude and appreciation to my thesis supervisors Prof. Yehea Ismail and Assoc. Prof. Hamdy Abd El. Hamid. Their guidance were crucial factors in the evolution of this work. I am thankful for the valuable insight stemming from their vast research experience that was conveyed throughout my research period. I would also like to especially thank Assoc. Prof. Hamdy Abd El Hamid for his continued support in the various directions of research and paper submissions. I also wish to thank my research colleague, Eng. Omnia Sami, who was of great help during the reliability modelling (NBTI), and for her help in the Multiphysics simulation tools. It is essential to thank Eng. Dalia Ahmed (CND Administration) for her continuous support and help with all the paperwork, guidelines and preparations needed for this thesis’ completion. I would also like to thank both my parents for their infinite faith in me. My mother’s research experience and achievements were the drive behind the completion of this work, and my father’s continued motivational support all the way through my graduate school years. I can never appreciate enough my younger brother, Ibrahim ElKashlan, who has always unconditionally supported and believed in me. My utmost gratitude goes towards my beloved aunt, Prof. Hana Soliman, for being my permanent source of strength throughout my studies. I am grateful for the presence of my family’s non-blood related member, Sima Habib, for being a source of my limitless drive from the beginning of my graduate studies and academic career. I cannot be grateful enough for Debbie Smith’s copy editing skills that were selflessly dedicated to the preparation of this thesis and my academic publications. I would also like to express my utmost appreciation for my long term best friend, Mariam Youniss, for her never ending support and faith. I dedicate a special thank you to every single person that showed their support and encouragement during the defense phase for this Thesis. Especially Dr. Nabil Hamdy for his caring words and incessant motivation prior to the defense. As well as every attendee that went out of their way to be present during the defense. I wish to thank my senior work colleagues; Eng. Mehaseb Ahmed, and Eng. Mahmoud Samy (Assistant Lecturers at Misr International University (MIU)) for their assistance in simulation tools, as well as my fellow junior work and study colleague Eng. Malak Yousry (AUC ECNG Graduate Student, Teaching Assistant at MIU) for her immeasurable encouragement. Finally, I would like to thank the MIU ECE department staff; most notably, Faculty Dean Prof. Hassan El-Ghitani, Dept. Head Dr. Alemam Said, Dr. Lamiaa ElKashan, and especially Dr. Lamiaa Sayed for their ceaseless motivation during my academic development.

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