DOCSLIB.ORG

A Dissertation Entitled Spectroscopic Ellipsometry Studies of Thin Film Si

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

A Dissertation entitled Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet by Laxmi Karki Gautam Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics _________________________________________ Dr. Nikolas J. Podraza, Committee Chair _________________________________________ Dr. Robert W. Collins, Committee Member _________________________________________ Dr. Randall Ellingson, Committee Member _________________________________________ Dr. Song Cheng, Committee Member _________________________________________ Dr. Rashmi Jha, Committee Member _________________________________________ Dr. Patricia R. Komuniecki, Dean College of Graduate Studies The University of Toledo May, 2016 Copyright 2016, Laxmi Karki Gautam This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet by Laxmi Karki Gautam Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics The University of Toledo May 2016 Optimization of thin film photovoltaics (PV) relies on the capability for characterizing the optoelectronic and structural properties of each layer in the device over large areas and correlating these properties with device performance. This work builds heavily upon that done previously by us, our collaborators, and other researchers. It provides the next step in data analyses, particularly that involving study of films in device configurations maintaining the utmost sensitivity within those same device structures. In this Dissertation, the component layers of thin film hydrogenated silicon (Si:H) solar cells on rigid substrate materials have been studied by real time spectroscopic ellipsometry (RTSE) and ex situ spectroscopic ellipsometry (SE). Growth evolution diagrams has been used to guide deposition of materials with good optoelectronic properties in the actual hydrogenated amorphous silicon (a-Si:H) PV device configuration. The nucleation and evolution of crystallites forming from the amorphous phase were studied using near infrared to ultraviolet spectroscopic ellipsometry in situ, during growth for films prepared as a function of hydrogen to reactive gas flow ratio R = [H2] /{[SiH4] + [Si2H6]. Furthermore, the major challenge in Si:H manufacturing is that iii quantitative analysis, characterization, and control of the relative nanocrystalline and amorphous volume fractions within mixed-phase films were covered during these studies. In conjunction with higher photon energy measurements, the presence and relative absorption strength of silicon-hydrogen infrared modes were measured by infrared extended ellipsometry measurements to gain some insight into chemical bonding. Structural and optical models have been developed for the back reflector (BR) structure consisting of sputtered undoped zinc oxide (ZnO) on top of silver (Ag) coated glass substrates. Characterization of the free-carrier absorption properties in Ag and the interface formed when Ag is over-coated with ZnO were also studied by infrared extended spectroscopic ellipsometry. Measurements ranging from 0.04 to 5 eV were used to extract layer thicknesses, composition, and optical response in the form of complex dielectric function spectra (ε = ε1 + iε2) for undoped a-Si:H layers in a substrate n-i-p a- Si:H based PV device structure and on TCO coated glass for p-i-n configurations. iv To my Family. Acknowledgements First of all, I would like to express my sincere gratitude to my supervisor Dr. Nikolas J. Podraza for his valuable guidance, unlimited support, expert mentoring, advice and encouragement throughout this work. His continuous guidance and support helped me to broaden my view and knowledge in subject matter. I would also like to extend my sincere gratitude to my committee members, Dr. Robert W. Collins, Dr. Randall Ellingson, Dr. Song Cheng and Dr. Rashmi Jha, for being in my committee and giving me valuable advices whenever needed. The laboratory support staff also has been very helpful and I would like to acknowledge support and the help I got from Terrance Kahle, Carl Salupo, and Nirupama Adiga. I would like to express my sincere gratitude to Dr. Patrick Hurley and Dr. Robert Ridgeway, and financial support from Air Products and Chemicals Inc. and Department of Energy (DE-EE0000580). I also thank Matthew L. Herold at the Air Force Institute of Technology Wright-Patterson Air Force Base for collaboration providing ZnO films. My deepest appreciation goes to all of my fellow research group members of the ellipsometry group and colleagues at the University of Toledo for motivating me and ensuring me to work in a very pleasant and comfortable environment. Most of all, my heartiest gratitude goes to my parent, my husband, Madhav, and daughter, Manasi, for supporting me under any circumstances. v Table of Contents Abstract .............................................................................................................................. iii Acknowledgements ..............................................................................................................v Table of Contents ............................................................................................................... vi List of Tables ................................................................................................................... ix List of Figures .................................................................................................................... xi 1 Introduction……. .....................................................................................................1 1.1 Motivation and Background ..............................................................................1 1.2 Dissertation Organization ..................................................................................9 2 Experimental Techniques used in Optical Measurements .....................................12 2.1 Deposition of Si:H Thin Films ........................................................................12 2.1.1 Cluster Tool Deposition System .......................................................14 2.1.2 Sputtering Process .............................................................................16 2.1.3 Plasma Enhanced Chemical Vapor Deposition ................................19 2.2 Material Characterization Techniques ............................................................21 2.2.1 Spectroscopic Ellipsometry ..............................................................21 2.2.1.1 Theoretical Formalism .......................................................23 2.2.1.2 Experimental Methods in Spectroscopic Ellipsometry ......33 2.2.1.3 Data Analysis Strategies in Spectroscopic Ellipsometry ...35 2.2.2 Experimental Methods in Solar Cell Characterization .....................45 vi 3 Growth Evolution of Si:H Prepared with Disilane Additives as Studied by Real Time Spectroscopic Ellipsometry ..........................................................................49 3.1 Introduction and Motivation ............................................................................49 3.2 Overview of Deposition Processes and Microstructural evolution..................50 3.2.1 Deposition Processes of Si:H Films ..................................................50 3.2.2 Microstructural Evolution and Phase Diagram .................................52 3.3 Experimental Details ........................................................................................59 3.4 S = 0, and variable R: Si:H Growth Evolution Baseline ..................................61 3.5 S = 0.12 and 1 and verses R: Effect of Disilane on Si:H Growth ....................63 3.6 Summary… ......................................................................................................67 4 Si:H Layer Optimization for Substrate Configuration of Solar Cell .....................69 4.1 Introduction ......................................................................................................69 4.2 Experimental Details ........................................................................................72 4.3 Ag/ZnO BR Substrate ......................................................................................73 4.4 n-layer Si:H on Ag/ZnO Substrate ...................................................................82 4.5 i-layer Si:H on Ag/ZnO/n-Si:H Substrate ........................................................85 4.6 p-layer Si:H on glass/i-layer Substrate ............................................................89 4.7 Summary… ......................................................................................................98 5 Growth and Analysis of Amorphous to Nanocrystalline Transition in Hydrogenated Silicon films ...................................................................................99 5.1 Introduction and Motivation ............................................................................99 5.2 Overview of Microstructural Evolution (a-Si:H to nc-Si:H) .........................102 5.3 Experimental Details ......................................................................................106 vii 5.4 Microstructural evolution of nc-Si:H
Recommended publications

  • Tin Doping Effect on Crystallization of Amorphous Silicon Obtained by Vapor Deposition in Vacuum

    Semiconductor Physics, Quantum Electronics & Optoelectronics, 2013. V. 16, N 4. P. 331-335. PACS 61.66.Dk, -f; 61.72.Cc, J-, Tt; 61.82.Fk; 71.55.Cn Tin doping effect on crystallization of amorphous silicon obtained by vapor deposition in vacuum V.B. Neimash1, V.M. Poroshin1, P.Ye. Shepeliavyi2, V.O. Yukhymchuk2, V.V. Melnyk3, V.A. Makara3, A.G. Kuzmich3 1Institute of Physics, NAS of Ukraine, 46, prospect Nauky, 03028 Kyiv, Ukraine 2V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 45, prospect Nauky, 03028 Kyiv, Ukraine 3Taras Shevchenko Kyiv National University, Physics Department, 60, Volodymyrska str., 01601 Kyiv, Ukraine Abstract. The influence of tin impurity on amorphous silicon crystallization was investigated using the methods of Raman scattering, Auger spectroscopy at ion etching, scanning electron microscopy and X-ray fluorescence microanalysis in thin films of Si:Sn alloy manufactured by thermal evaporation. Formation of Si crystals of the 2 to 4- nm size has been found in the amorphous matrix alloy formed at the temperature 300 C. Total volume of nanocrystals correlates with the content of tin and can comprise as much as 80% of the film. The effect of tin-induced crystallization of amorphous silicon occurred only if there are clusters of metallic tin in the amorphous matrix. The mechanism of tin-induced crystallization of silicon that has been proposed takes into account the processes in eutectic layer at the interface metal tin – amorphous silicon. Keywords: nanocrystalline silicon, amorphous silicon, thin films, Si:Sn alloy. Manuscript received 06.08.13; revised version received 26.09.13; accepted for publication 23.10.13; published online 16.12.13.
  • Advances in Photovoltaics: Part 3 SERIES EDITORS

    Advances in Photovoltaics: Part 3 SERIES EDITORS

    VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 SERIES EDITORS EICKE R. WEBER Director Fraunhofer-Institut fur€ Solare Energiesysteme ISE Vorsitzender, Fraunhofer-Allianz Energie Heidenhofstr. 2, 79110 Freiburg, Germany CHENNUPATI JAGADISH Australian Laureate Fellow and Distinguished Professor Department of Electronic Materials Engineering Research School of Physics and Engineering Australian National University Canberra, ACT 0200 Australia VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 Edited by GERHARD P. WILLEKE Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany EICKE R. WEBER Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Academic Press is an imprint of Elsevier 32 Jamestown Road, London NW1 7BY, UK 525 B Street, Suite 1800, San Diego, CA 92101-4495, USA 225 Wyman Street, Waltham, MA 02451, USA The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK First edition 2014 Copyright © 2014 Elsevier Inc. All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).
  • Characterization of an Active Metasurface Using Terahertz Ellipsometry Nicholas Karl, Martin S

    Characterization of an Active Metasurface Using Terahertz Ellipsometry Nicholas Karl, Martin S

    Characterization of an active metasurface using terahertz ellipsometry Nicholas Karl, Martin S. Heimbeck, Henry O. Everitt, Hou-Tong Chen, Antoinette J. Taylor, Igal Brener, Alexander Benz, John L. Reno, Rajind Mendis, and Daniel M. Mittleman Citation: Appl. Phys. Lett. 111, 191101 (2017); View online: https://doi.org/10.1063/1.5004194 View Table of Contents: http://aip.scitation.org/toc/apl/111/19 Published by the American Institute of Physics APPLIED PHYSICS LETTERS 111, 191101 (2017) Characterization of an active metasurface using terahertz ellipsometry Nicholas Karl,1 Martin S. Heimbeck,2 Henry O. Everitt,2 Hou-Tong Chen,3 Antoinette J. Taylor,3 Igal Brener,4 Alexander Benz,4 John L. Reno,4 Rajind Mendis,1 and Daniel M. Mittleman1 1School of Engineering, Brown University, 184 Hope St., Providence, Rhode Island 02912, USA 2U.S. Army AMRDEC, Redstone Arsenal, Huntsville, Alabama 35808, USA 3Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA 4Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA (Received 11 September 2017; accepted 19 October 2017; published online 6 November 2017) Switchable metasurfaces fabricated on a doped epi-layer have become an important platform for developing techniques to control terahertz (THz) radiation, as a DC bias can modulate the transmis- sion characteristics of the metasurface. To model and understand this performance in new device configurations accurately, a quantitative understanding of the bias-dependent surface characteristics is required. We perform THz variable angle spectroscopic ellipsometry on a switchable metasur- face as a function of DC bias. By comparing these data with numerical simulations, we extract a model for the response of the metasurface at any bias value.
  • Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

    Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

    hv photonics Article Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy Najat Andam 1,2 , Siham Refki 2, Hidekazu Ishitobi 3,4, Yasushi Inouye 3,4 and Zouheir Sekkat 1,2,4,* 1 Department of Chemistry, Faculty of Sciences, Mohammed V University, Rabat BP 1014, Morocco; [email protected] 2 Optics and Photonics Center, Moroccan Foundation for Advanced Science, Innovation and Research, Rabat BP 10100, Morocco; [email protected] 3 Frontiers Biosciences, Osaka University, Osaka 565-0871, Japan; [email protected] (H.I.); [email protected] (Y.I.) 4 Department of Applied Physics, Osaka University, Osaka 565-0871, Japan * Correspondence: [email protected] Abstract: The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the Citation: Andam, N.; Refki, S.; Ishitobi, H.; Inouye, Y.; Sekkat, Z.
  • Progress in Hot-Wire Deposited Nanocrystalline Silicon Solar Cells

    Progress in Hot-Wire Deposited Nanocrystalline Silicon Solar Cells

    DEPARTAMENT DE FÍSICA APLICADA I ÒPTICA Av. Diagonal, 647, 08028 Barcelona PROGRESS IN HOT-WIRE DEPOSITED NANOCRYSTALLINE SILICON SOLAR CELLS Marta Fonrodona Turon Memòria presentada per optar al grau de Doctor Barcelona, juny de 2003 DEPARTAMENT DE FÍSICA APLICADA I ÒPTICA Av. Diagonal, 647, 08028 Barcelona PROGRESS IN HOT-WIRE DEPOSITED NANOCRYSTALLINE SILICON SOLAR CELLS Marta Fonrodona Turon Programa de doctorat: Tècniques Instrumentals de la Física i la Ciència de Materials Bienni: 1998-2000 Tutor: Enric Bertran Serra Director: Joan Bertomeu i Balagueró Memòria presentada per optar al grau de Doctor Barcelona, juny de 2003 A la Pepeta, la Núria i tots els que hi ha entremig. This work has been carried out in the Laboratory of Thin Film Materials of the Department of Applied Physics and Optics of the University of Barcelona, supervised by Dr. Joan Bertomeu Balagueró, in the framework of the projects TIC98-0381-C0201 and MAT2001-3541-C03-01 of the CICYT of the Spanish Government , and also with the aid of the project JOR3-CT97-0126 in the JOULE programme of the European Commission. The stage at Utrecht University was possible thanks to grant 2001BEAI200159 of Generalitat de Catalunya. Progress in Hot-Wire deposited nanocrystalline silicon solar cells 1 &RQWHQWV Agraïments ............................................................................................................................3 1- Introduction .......................................................................................................................5 1.1-
  • Use of Spectroscopic Ellipsometry and Modeling in Determining Composition and Thickness of Barium Strontium Titanate Thin-Films

    Use of Spectroscopic Ellipsometry and Modeling in Determining Composition and Thickness of Barium Strontium Titanate Thin-Films

    Use of Spectroscopic Ellipsometry and Modeling in Determining Composition and Thickness of Barium Strontium Titanate Thin-Films A Thesis Submitted to the Faculty of Drexel University by Dominic G. Bruzzese III in partial fulfillment of the requirements for the degree of MS in Materials Science and Engineering June 2010 c Copyright June 2010 Dominic G. Bruzzese III. All Rights Reserved. Acknowledgements I would like to acknowledge the guidance and motivation I received from my advi- sor Dr. Jonathan Spanier not just during my thesis but for my entire stay at Drexel University. Eric Gallo for his help as my graduate student mentor and always making himself available to help me with everything from performing an experiment to ana- lyzing some result, he has been an immeasurable resource. Keith Fahnestock and the Natural Polymers and Photonics Group under the direction of Dr. Caroline Schauer for allowing the use of their ellipsometer, without which this work would not have been possible. I would like to thank everyone in the MesoMaterials Laboratory, espe- cially Stephen Nonenmann, Stephanie Johnson, Guannan Chen, Christopher Hawley, Brian Beatty, Joan Burger, and Andrew Akbasheu for help with experiments, as well as Oren Leffer and Terrence McGuckin for enlightening discussions. Claire Weiss and Dr. Pamir Alpay at the University of Connecticut have both contributed much to the the field and I am grateful for their work; also Claire produced the MOSD samples on which much of the characterization and modeling was done. Dr. Melanie Cole and the Army Research Office and Dr. Marc Ulrich for funding the project under W911NF-08-0124 and W911NF-08-0067.
  • Ellipsometry

    Ellipsometry

    AALBORG UNIVERSITY Institute of Physics and Nanotechnology Pontoppidanstræde 103 - 9220 Aalborg Øst - Telephone 96 35 92 15 TITLE: Ellipsometry SYNOPSIS: This project concerns measurement of the re- fractive index of various materials and mea- PROJECT PERIOD: surement of the thickness of thin films on sili- September 1st - December 21st 2004 con substrates by use of ellipsometry. The el- lipsometer used in the experiments is the SE 850 photometric rotating analyzer ellipsome- ter from Sentech. THEME: After an introduction to ellipsometry and a Detection of Nanostructures problem description, the subjects of polar- ization and essential ellipsometry theory are covered. PROJECT GROUP: The index of refraction for silicon, alu- 116 minum, copper and silver are modelled us- ing the Drude-Lorentz harmonic oscillator model and afterwards measured by ellipsom- etry. The results based on the measurements GROUP MEMBERS: show a tendency towards, but are not ade- Jesper Jung quately close to, the table values. The mate- Jakob Bork rials are therefore modelled with a thin layer of oxide, and the refractive indexes are com- Tobias Holmgaard puted. This model yields good results for the Niels Anker Kortbek refractive index of silicon and copper. For aluminum the result is improved whereas the result for silver is not. SUPERVISOR: The thickness of a thin film of SiO2 on a sub- strate of silicon is measured by use of ellip- Kjeld Pedersen sometry. The result is 22.9 nm which deviates from the provided information by 6.5 %. The thickness of two thick (multiple wave- NUMBERS PRINTED: 7 lengths) thin polymer films are measured. The polymer films have been spin coated on REPORT PAGE NUMBER: 70 substrates of silicon and the uniformities of the surfaces are investigated.
  • 1. Introduction & Theory

    1. Introduction & Theory

    1. Introduction & Theory Neha Singh October 2010 Course Overview Day 1: Day 2: Introduction and Theory Genosc Layer Transparent Films Absorbing Films Microstructure – EMA If time permits: – Surface roughness Non-idealities – Grading (Simple and Ultra thin films function-based ITO) Uniqueness test – Thickness non-uniformity UV Absorption Review – Point-by-point fit Actual Samples © 2010, All Rights Reserved 2 Introduction & Theory Light Materials (optical constants) Interaction between light and materials Ellipsometry Measurements Data Analysis © 2010, All Rights Reserved 3 Light Electromagnetic Plane Wave From Maxwell’s equations we can describe a plane wave ⎛ 2π ⎞ E(z,t) = E0 sin⎜ − (z − vt) + ξ ⎟ ⎝ λ ⎠ Amplitude Amplitude arbitraryarbitrary phase phase X Wavelength Wavelength VelocityVelocity λ Electric field E(z,t) Y Z Direction Magnetic field, B(z,t) of propagation © 2010, All Rights Reserved 4 Intensity and Polarization Intensity = “Size” of Electric field. I ∝ E 2 Polarization = “Shape” of Electric field travel. Different Size Y •Y E More Intense Less (Intensity) Intense E Same Shape! X (Polarization) •X © 2010, All Rights Reserved 5 What is Polarization? Describes how Electric Field travels through space and time. X wave1 Y E wave2 Z © 2010, All Rights Reserved 6 Describing Polarized Light Jones Vector Stokes Vector Describe polarized light Describe any light beam with amplitude & phase. as vector of intensity ⎡S ⎤ ⎡ E2 + E2 ⎤ iϕx 0 x0 y0 ⎡Ex ⎤ ⎡E0xe ⎤ ⎢ ⎥ ⎢ 2 2 ⎥ = S1 ⎢ Ex0 −Ey0 ⎥ ⎢ ⎥ ⎢ iϕy ⎥ ⎢ ⎥ = E E e ⎢ ⎥ ⎢ ⎥ ⎣ y ⎦ ⎣⎢ 0y ⎦⎥ S2 2Ex0Ey0 cosΔ ⎢ ⎥ ⎢ ⎥ ⎣S3 ⎦ ⎣⎢2Ex0Ey0 sinΔ⎦⎥ © 2010, All Rights Reserved 7 Light-Material Interaction velocity & c wavelength vary v = in different n materials n = 1 •n = 2 Frequency remains constant v υ = λ © 2010, All Rights Reserved What are Optical Constants n , k Describe how materials and light interact.
  • Crystalline-Silicon Solar Cells for the 21St Century

    Crystalline-Silicon Solar Cells for the 21St Century

    May 1999 • NREL/CP-590-26513 Crystalline-Silicon Solar Cells for the 21st Century Y.S. Tsuo, T.H. Wang, and T.F. Ciszek Presented at the Electrochemical Society Annual Meeting Seattle, Washington May 3, 1999 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute ••• Battelle ••• Bechtel Contract No. DE-AC36-98-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Available to DOE and DOE contractors from: Office of Scientific and Technical Information (OSTI) P.O. Box 62 Oak Ridge, TN 37831 Prices available by calling 423-576-8401 Available to the public from: National Technical Information Service (NTIS) U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 703-605-6000 or 800-553-6847 or DOE Information Bridge http://www.doe.gov/bridge/home.html Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste CRYSTALLINE-SILICON SOLAR CELLS FOR THE 21ST CENTURY Y.S.
  • Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon

    Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon

    The University of Southern Mississippi The Aquila Digital Community Dissertations Summer 2019 Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon Durga Prasad Paudel University of Southern Mississippi Follow this and additional works at: https://aquila.usm.edu/dissertations Part of the Condensed Matter Physics Commons, Other Physics Commons, and the Statistical, Nonlinear, and Soft Matter Physics Commons Recommended Citation Paudel, Durga Prasad, "Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon" (2019). Dissertations. 1686. https://aquila.usm.edu/dissertations/1686 This Dissertation is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Dissertations by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. MORPHOLOGICAL STUDY OF VOIDS IN ULTRA-LARGE MODELS OF AMORPHOUS SILICON by Durga Prasad Paudel A Dissertation Submitted to the Graduate School, the College of Arts and Sciences and the School of Mathematics and Natural Sciences at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Approved by: Dr. Parthapratim Biswas, Committee Chair Dr. Chris Winstead Dr. Khin Maung Maung Dr. Ras B. Pandey Dr. Gopinath Subramanian Dr. Parthapratim Biswas Dr. Bernd Schroeder Dr. Karen S. Coats Committee Chair Director of School Dean of the Graduate School August 2019 COPYRIGHT BY DURGA PRASAD PAUDEL 2019 ABSTRACT The microstructure of voids in pure and hydrogen-rich amorphous silicon (a:Si) network was studied in ultra-large models of amorphous silicon, using classical and quantum- mechanical simulations, on the nanometer length scale.
  • Optical Properties of Teflon AF Amorphous Fluoropolymers

    Optical Properties of Teflon AF Amorphous Fluoropolymers

    J. Micro/Nanolith. MEMS MOEMS 7͑3͒, 033010 ͑Jul–Sep 2008͒ Optical properties of Teflon® AF amorphous fluoropolymers MinK.Yang Abstract. The optical properties of three grades of Teflon® AF— Roger H. French AF1300, AF1601, and AF2400—were investigated using a J.A. Woollam DuPont Co. Central Research VUV-VASE spectroscopic ellipsometry system. The refractive indices for Experimental Station each grade were obtained from multiple measurements with different film Wilmington, Delaware 19880-0400 thicknesses on Si substrates. The absorbances of Teflon® AF films were E-mail: [email protected] determined by measuring the transmission intensity of Teflon® AF films on CaF2 substrates. In addition to the refractive index and absorbance per cm ͑base 10͒, the extinction coefficient ͑k͒, and absorption coefficient Edward W. Tokarsky ͑␣͒ per cm ͑base e͒, Urbach parameters of absorption edge position and DuPont Fluoropolymer Solutions edge width, and two-pole Sellmeier parameters were determined for the Chestnut Run Plaza three grades of Teflon® AF. We found that the optical properties of the Wilmington, Delaware 19880-0713 three grades of Teflon® AF varied systematically with the AF TFE/PDD composition. The indices of refraction, extinction coefficient ͑k͒, absorp- tion coefficient ͑␣͒, and absorbance ͑A͒ increased, as did the TFE con- tent, while the PDD content decreased. In addition, the Urbach edge position moved to a longer wavelength, and the Urbach edge width became wider. © 2008 Society of Photo-Optical Instrumentation Engineers. ͓DOI: 10.1117/1.2965541͔ Subject terms: fluoropolymer; absorbance absorption coefficient; VUV ellipsometry. Paper 07086R received Oct. 24, 2007; revised manuscript received May 16, 2008; accepted for publication Jun.
  • Ellipsometry for Csige Metrology

    Ellipsometry for Csige Metrology

    Ellipsometry for cSiGe Metrology Saiqa Farhat, Srinivasan Rangarajan, Timothy J. Dawei Hu, Ming Dai Mcardle, Michael Steigerwalt Films Metrology Division 300mm East Fishkill KLA Tencor Corp. IBM Corp San Jose, CA Hopewell Jn, NY, USA Abstract— In this paper we report the effectiveness of sensitive to the refractive index and thickness of the films in optical ellipsometry in measuring thickness and Germanium % the stack. Next, the elliptically polarized light will pass through of channel SiGe on SOI substrate used in advanced node high the analyzer and become linear polarized light again. Finally, performance semiconductor devices. the detector will receive the linear polarized light signal. The value tanΨ and cosΔ are extracted as a function of wavelength. Keywords—cSiGe, Ellipsometry, Thickness, Ge These are called the measured spectra. Concentration, metrology. I. INTRODUCTION Optical metrology of film thickness is the “work-horse” technique in semiconductor fabrication for control of a wide variety of processes. The tools and their technology are well established, providing low cost of ownership (COO) to manufacturers by giving fast and reliable feedback to their processes. In this study we demonstrate the successful implementation of optical metrology for cSiGe process control replacing a X-ray diffraction technique. The performance of SiGe channel in devices is dependent on film thickness and %Ge. X-ray diffraction (XRD) technique measures the change Figure 1: SE measurement optics schematic in lattice spacing of the strained silicon which is well correlated with %Ge in the film [1]. The technique is slow and new, posing challenges in manufacturing. Optical metrology on the other hand is a model based technique relying on the ability to B.