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Growth, Optimization, and Characterization of Transition Metal GROWTH, OPTIMIZATION, AND CHARACTERIZATION OF TRANSITION METAL NITRIDES AND TRANSITION METAL OXIDES FOR ELECTRONIC AND OPTICAL APPLICATIONS Thesis Submitted to The School of Engineering of the UNIVERSITY OF DAYTON In Partial Fulfillment of the Requirements for The Degree of Master of Science in Electro-Optics By Zachary Biegler UNIVERSITY OF DAYTON Dayton, Ohio December 2019 GROWTH, OPTIMIZATION, AND CHARACTERIZATION OF TRANSITION METAL NITRIDES AND TRANSITION METAL OXIDES FOR ELECTRONIC AND OPTICAL APPLICATIONS Name: Biegler, Zachary Jay APPROVED BY: Andrew Sarangan, Ph.D., P.E. Amber Reed, Ph.D. Advisory Committee Chairman Committee Member Professor Materials Engineer Department of Electro-Optics and Photonics AFRL/RXAN Partha Banerjee, Ph.D. Committee Member Professor Department of Electro-Optics and Photonics Robert J. Wilkens, Ph.D., P.E. Eddy M. Rojas, Ph.D., M.A., P.E. Associate Dean for Research and Innovation Dean, School of Engineering Professor School of Engineering ii ABSTRACT GROWTH, OPTIMIZATION, AND CHARACTERIZATION OF TRANSITION METAL NITRIDES AND TRANSITION METAL OXIDES FOR ELECTRONIC AND OPTICAL APPLICATIONS Name: Biegler, Zachary J. University of Dayton Advisor: Dr. Andrew Sarangan The next generation of electronic and optical devices require high quality, crystalline materials in order to obtain relevant properties for novel devices. Two classes of materials offer unique material properties that can satisfy the requirements for next generation devices. These two classes of materials are the transition metal nitrides (TMNs) and transition metal oxides (TMOs). These materials offer electronic properties that range from conductive, metallic, materials to semiconducting and insulating materials. However, for many optical and electronic applications, the band structure and crystalline symmetries must be preserved. This work examines the growth and characterization of the TMN materials AlN and ScN as well as the TMO materials VO2 and TiO2. In all these materials, the crystalline structure plays and extremely important role in the desired properties. In addition, incorporation of other impurities can detrimentally impact the functionality of these film materials. In order to minimize the impurity incorporation and maintain the crystalline structure, the growth of AlN, ScN, VO2, and TiO2 films by various deposition techniques were examined and optimized. This allowed growth of high quality TMN and TMO materials that resulted in iii characterization and optimization of the relevant optical, electronic, and structural properties and, somewhat, the degree to which these properties could be tuned through growth conditions. iv DEDICATION This work is dedicated to my parents and siblings. v ACKNOWLEDGMENTS This work would not have been possible without the help and guidance from so many different people. My advisors Dr. Andrew Sarangan and Dr. Amber Reed both spent many hours helping me get into a field of study of which I was not familiar. Words cannot express how much their guidance and patience means to me. I also would like to thank Dr. Kurt Eyink, Dr. Tyson Back, Dr. John Centar, and Dr. David Look for all of their help taking data and discussing results obtained through the characterization of these films. Dr. Dean Brown provided COMSOL simulations of the magnetic fields in the unbalanced magnetron system. In addition, none of this work could have been possible without the help of Hadley Smith and Rachel Adams who helped with sample growth and XRD characterization of some of the TMN materials. Dr. Pengfei Guo was instrumental in the growth of VO2 by thermal oxidation. Last, but certainly not least, I want to thank Madelyn Hill for all of the AFM surface analysis that was performed in this work as well as Dr. Albert Hilton for the piezoelectric force microscopy measurements. Additionally, none of the transition metal nitride work could have commenced without the support of AFOSR under the award number FA9550-17RYCOR490. vi TABLE OF CONTENTS ABSTRACT ....................................................................................................................... iii DEDICATION .................................................................................................................... v ACKNOWLEDGMENTS ................................................................................................. vi LIST OF FIGURES ............................................................................................................ x LIST OF ABBREVIATIONS AND NOTATIONS ......................................................... xv CHAPTER 1 INTRODUCTION TO MATERIAL SYSTEMS ......................................... 1 1.1 Transition Metal Nitrides ..................................................................................... 2 1.1.1 Titanium Nitride............................................................................................ 3 1.1.2 Scandium Nitride .......................................................................................... 4 1.1.3 Aluminum Nitride ......................................................................................... 5 1.2 Transition Metal Oxides ....................................................................................... 9 1.2.1 Vanadium Oxide ........................................................................................... 9 1.2.2 Titanium Oxide ........................................................................................... 12 CHAPTER 2 GROWTH SYSTEMS ................................................................................ 15 2.1 DC Sputtering System ........................................................................................ 15 2.1.1 Sputter Deposition ...................................................................................... 15 2.1.2 Reactive Sputtering ..................................................................................... 17 2.1.3 Magnetron Sputtering ................................................................................. 18 2.1.4 Sputtering System ....................................................................................... 21 2.2 Controllably-Unbalanced DC Reactive Magnetron Sputtering ......................... 22 2.2.1 Unbalanced Magnetron Sputtering ............................................................. 23 vii 2.2.2 Controllably-Unbalanced Sputtering System ............................................. 26 2.3 Ion Assisted Evaporation System ....................................................................... 30 2.3.1 Thermal Evaporation .................................................................................. 31 2.3.2 Ion Assisted Evaporation ............................................................................ 33 2.3.3 IAD System ................................................................................................. 34 CHAPTER 3 CHARACTERIZATION TECHNIQUES .................................................. 37 3.1 X-Ray Diffractometry ........................................................................................ 37 3.1.1 Introduction to XRD ................................................................................... 38 3.1.2 Grazing Incident X-Ray Diffraction ........................................................... 44 3.1.3 Coupled Scans ............................................................................................. 46 3.1.3.1 Symmetric Coupled Scans ................................................................... 46 3.1.3.2 Asymmetric Coupled Scans ................................................................. 52 3.1.4 Rocking Curves ........................................................................................... 54 3.1.5 Pole Figures ................................................................................................ 56 3.2 X-Ray Photoelectron Spectroscopy ................................................................... 59 3.3 Secondary Ion Mass Spectrometry ..................................................................... 62 3.4 Spectroscopic Ellipsometry ................................................................................ 63 3.5 Hall Effect and Transport ................................................................................... 68 CHAPTER 4 SCANDIUM NITRIDE GROWTH AND CHARACTERIZATION ........ 72 4.1 Nitrogen Fraction ............................................................................................... 76 4.2 Magnetron Power ............................................................................................... 79 4.3 Substrate Temperature........................................................................................ 81 4.4 Final Optimization.............................................................................................. 84 viii 4.5 ScN Optical and Electronic Properties ............................................................... 91 CHAPTER 5 ALUMINUM NITRIDE GROWTH AND CHARACTERIZATION ....... 99 5.1 Nitrogen Fraction ............................................................................................... 99 5.2 Substrate Temperature...................................................................................... 104 5.3 Coil Current ...................................................................................................... 108 5.4 Magnetron Power ............................................................................................. 112 5.5 Final
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