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Hung Viet Pham FABRICATION AND ELECTRICAL CHARACTERISATION OF GRAPHITIC SCHOTTKY CONTACTS TO SILICON, SILICON CARBIDE AND GALLIUM OXIDE A thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy Hung Viet Pham Master of Electrical and Computer Engineering by RMIT University School of Engineering College of Science, Engineering and Health RMIT University August 2019 AUTHOR’S DECLARATION I certify that except where due acknowledgement has been made, the work is that of the author alone; the work has not been submitted previously, in whole or in part, to qualify for any other academic award; the content of the thesis is the result of work, which has been carried out since the official commencement date of the approved research program; any editorial work, paid or unpaid, carried out by a third party is acknowledged. Hung Viet Pham 02/08/2019 ii ACKNOWLEDGMENTS This PhD thesis cannot be accomplished without the support, advice and encouragement from many sincere and generous people. I want to show special appreciation to my supervisor, Associate Professor Anthony Holland, for his constant academic guidance throughout my PhD candidature at RMIT University. I will always be impressed and grateful for your dedication toward student despite of distance and time. I would also like to send the deepest gratitude to my co-senior supervisor, Doctor James Partridge. Your professional and disciplined hard-working attitude as well as your broad Physics insight has become the model for me to learn and follow. My appreciation extends to many staffs and friends at RMIT Vietnam who support in laboratory and administration, especially Head of School of Science and Technology Associate Professor Alex Stocevski and Professor Eric Dimla who provided strong academic environment to support PhD students. Within a short period of time in RMIT Melbourne, I had the opportunities to work intensively in RMMF (RMIT Microscopy and Microanalysis Facility) to fulfill my PhD. This visit cannot happen without sponsorship from Doctor James Partridge and Professor Dougal McCulloch, and relentless effort of Associate Professor Anthony Holland. I also want to thank Hiep Tran, Tuan Bui and Phuong Le for their enthusiastic support during my time in Melbourne. Finally, I send special thanks to all my friends and colleagues who walk along with me through the long journey. iii PUBLICATIONS Journal publication: [1] H. V. Pham et al., "Temperature dependent electrical characteristics of rectifying graphitic contacts to p-type silicon," Semiconductor Science and Technology, vol. 34, no. 1, p. 015003, 2018. [2] H. Pham, H. N. Tran, A. S. Holland, and J. G. Partridge, "Temperature-Dependent Electrical Characteristics and Extraction of Richardson Constant from Graphitic- C/n-Type 6H-SiC Schottky Diodes," Journal of Electronic Materials, pp. 1-6, 2019. This article has been chosen by the Editors of the Journal of Electronic Materials to appear on Springer's website as a "Free Access" article. IEEE Conference Proceeding [3] Hung V. Pham, N. Le Huy, A. Stojcevski, and A. S. Holland, "Impact of impurities in 4H, 6H and 3C-SiC substrate on reverse recovery time of pn junction," in Information Science and Technology (ICIST), 2017 Seventh International Conference on, 2017, pp. 299-303: IEEE. [4] Hung V. Pham, A. S. Holland, H. L. Nguyen, J. G. Partridge, and H. N. Tran, "Modified electrical characteristics of filtered cathodic vacuum arc amorphous carbon film on n-Si (100) by heat treatment," in Micro and Nanoelectronics (RSM), 2017 IEEE Regional Symposium on, 2017, pp. 38-41: IEEE. [5] Hung V. Pham, S. N. Demidenko, and G. M. Merola, "Eliminating Re-Burn-In in semiconductor manufacturing through statistical analysis of production test data," iv in Instrumentation and Measurement Technology Conference (I2MTC), 2017 IEEE International, 2017, pp. 1-6: IEEE. [6] H. V. Pham, S. Luong, A. S. Holland, and H. L. Nguyen, "Impact of temperature on electrical performance of Ni film on n-type 4H-SÌC contacts in terms of micropipes density," in Recent Advances in Signal Processing, Telecommunications & Computing (SigTelCom), 2018 2nd International Conference on, 2018, pp. 132-135: IEEE. v TABLE OF CONTENTS AUTHOR’S DECLARATION ........................................................................................... ii ACKNOWLEDGMENTS ................................................................................................. iii PUBLICATIONS ............................................................................................................... iv TABLE OF CONTENTS ................................................................................................... vi LIST OF FIGURES ............................................................................................................ x LIST OF TABLES ............................................................................................................ xv LIST OF SYMBOLS ....................................................................................................... xvi LIST OF SYNONYMS.................................................................................................. xviii ABSTRACT ..................................................................................................................... xix CHAPTER 1 INTRODUCTION ........................................................................................ 1 1.1 Motivation and rationale ..................................................................................... 1 1.2 Silicon ................................................................................................................. 2 1.3 Silicon Carbide ................................................................................................... 4 1.4 Gallium Oxide ..................................................................................................... 8 1.5 Challenges for high power devices ................................................................... 10 1.6 Schottky diodes ................................................................................................. 11 1.6.1 Brief overview of metal-semiconductor junction formation and electrical properties ................................................................................................................... 14 1.6.2 Application .................................................................................................... 16 1.7 Carbon materials ............................................................................................... 16 vi 1.8 Experiment activities ........................................................................................ 19 1.9 Thesis organization ........................................................................................... 20 1.10 References ......................................................................................................... 21 CHAPTER 2 BACKGROUND AND RECENT ADVANCES IN CARBON-BASED SCHOTTKY DEVICES ................................................................................................... 31 2.1 Introduction ....................................................................................................... 31 2.2 Schottky diode .................................................................................................. 31 2.2.1 Interface states .............................................................................................. 34 2.2.2 Image force lowering .................................................................................... 36 2.2.3 Current-voltage characteristics ..................................................................... 38 2.2.4 Current transportation ................................................................................... 39 2.2.5 Schottky barrier inhomogeneity .................................................................... 45 2.3 Carbon-semiconductor Schottky diodes ........................................................... 48 2.4 Summary ........................................................................................................... 57 2.5 References ......................................................................................................... 58 CHAPTER 3 FABRICATION & CHARACTERISATION METHODS ........................ 65 3.1 Schottky diode fabrication ................................................................................ 65 3.1.1 Substrate dicing ............................................................................................. 65 3.1.2 Wafer cleaning .............................................................................................. 66 3.1.3 Spin coating .................................................................................................. 67 3.1.4 Mask alignment and UV exposure ................................................................ 68 3.1.5 Energetic carbon deposition using a filtered cathodic vacuum arc (FCVA) 70 3.1.6 Ion beam sputtering of metallic device contact layers .................................. 73 3.2 Electrical characterization ................................................................................. 74 3.2.1 Current-voltage characterization ................................................................... 74 3.2.2 Temperature dependent electrical measurements ......................................... 75 vii 3.2.3 Capacitance-voltage characterization ..........................................................
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