Rochester Institute of Technology RIT Scholar Works Theses 8-30-2013 Comprehensive Mapping and Benchmarking of Esaki Diode Performance David John Pawlik Follow this and additional works at: https://scholarworks.rit.edu/theses Part of the Electronic Devices and Semiconductor Manufacturing Commons, and the Other Electrical and Computer Engineering Commons Recommended Citation Pawlik, David John, "Comprehensive Mapping and Benchmarking of Esaki Diode Performance" (2013). Thesis. Rochester Institute of Technology. Accessed from This Dissertation is brought to you for free and open access by RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. R I T Comprehensive Mapping and Benchmarking of Esaki Diode Performance by David John Pawlik A dissertation submitted in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Microsystems Engineering Microsystems Engineering Program Kate Gleason College of Engineering Rochester Institute of Technology Rochester, New York August 30, 2013 Comprehensive Mapping and Benchmarking of Esaki Diode Performance by David Pawlik Committee Approval: We, the undersigned committee members, certify that we have advised and/or supervised the candidate on the work described in this dissertation. We further certify that we have reviewed the dissertation manuscript and approve it in partial fulfillment of the requirements of the degree of Doctor of Philosophy in Microsystems Engineering. ______________________________________________________________________________ Prof. Sean L. Rommel Date Associate Professor, Electrical and Microelectronic Engineering Department ______________________________________________________________________________ Prof. Santosh K. Kurinec Date Professor, Electrical and Microelectronic Engineering Department ______________________________________________________________________________ Prof. Seth Hubbard Date Associate Professor, Physics Department ______________________________________________________________________________ Prof. Suman Datta Date Professor, Electrical Engineering Department ______________________________________________________________________________ Prof. Andreas Savakis Date Professor, Computer Engineering Department Certified by: ______________________________________________________________________________ Prof. Bruce Smith Date Director, Microsystems Engineering Program ______________________________________________________________________________ Prof. Harvey Palmer Date Dean, Kate Gleason College of Engineering ii ABSTRACT Kate Gleason College of Engineering Rochester Institute of Technology Degree : Doctor of Philosophy Program : Microsystems Engineering Authors Name: David John Pawlik Advisors Name: Prof. Sean L. Rommel Dissertation Title: Comprehensive Mapping and Benchmarking of Esaki Diode Performance The tunneling-FET (TFET) has been identified as a prospective MOSFET replacement technology with the potential to extend geometric and electrostatic scaling of digital integrated circuits. However, experimental demonstrations of the TFET have yet to reliably achieve drive currents necessary to power large scale integrated circuits. Consequentially, much effort has gone into optimizing the band-to-band tunneling (BTBT) efficiency of the TFET. In this work, the Esaki tunnel diode (ETD) is used as a short loop element to map and optimize BTBT performance for a large design space. The experimental results and tools developed for this work may be used to (1) map additional and more complicated ETD structures, (2) guide development of improved TFET structures and BTBT devices, (3) design ETDs targeted BTBT characteristics, and (4) calibrate BTBT models. The first objective was to verify the quality of monolithically integrated III-V based ETDs on Si substrates (the industry standard). Five separate GaAs/InGaAs ETDs were fabricated on GaAs-virtual substrates via aspect ratio trapping, along with two companion ETDs grown on Si and GaAs bulk substrates. The quality of the virtual substrates and BTBT were verified with (i) very large peak-valley current ratios (up to 56), (ii) temperature measurements, and (iii) deep sub-micron scaling. The second objective mapped the BTBT characteristics of the In 1-xGa xAs ternary system by (1) standardizing the ETD structure, (2) limiting experimental work to unstrained (i) GaAs, (ii) In 0.53 Ga 0.47 As, and (iii) InAs homojunctions, and (3) systematically varying doping concentrations. Characteristic BTBT trendlines were determined for each material system, ranging from ultra-low to ultra-high peak 2 2 current densities ( JP) of 11 µA/cm to 975 kA/cm for GaAs and In 0.53 Ga 0.47 As, respectively. Furthermore, the BTBT mapping results establishes that BTBT current densities can only be improved by ~2-3 times the current record, by increasing doping concentration and In content up to ~75%. The E. O. Kane BTBT model has been shown to accurately predict the tunneling characteristics for the entire design space. Furthermore, it was used to help guide the development of a new universal BTBT model, which is a closed form exponential using 2 fitting parameters, material constants, and doping concentrations. With it, JP can quickly be predicted over the entire design space of this work. iii ACKNOWLEDGMENTS It was my parents (John and Diane) who, through their nurturing and encouragement, set me on the path towards becoming an intellectual in the areas of math, science, and engineering. They never needed to push me in any direction. However they were, and are, great at showing me the various avenues of approach and helping me peer down the way to judge the best course of action. I am forever grateful to them for being superb parents. I never doubted being able to complete this dream, just like I know they will always be there for me (in one way or another). Their work ethic and strength of character continually inspires me to improve my own character. I also want to thank my brother, Michael, who has always had my back. His support and encouragement has always been there, sometimes behind the scenes, even when I didn’t realize I needed it. Recently he has shown me, by example, what it takes to be a strong and effective family member. Prof. Rommel is personally responsible for retaining me at RIT for many years past my undergraduate days, and I have loved all of it. As an intern in his research group I fell in love with the topic area, and gained a great relationship with my advisor and mentor. I cannot imagine having completed this work with anyone else. I know that we will continue our friendship into the future, and look forward to many more discussions regarding research, lab work, fellow researchers, and of course pop culture science fiction. I would like to thank Prof. Lynn Fuller for stimulating my initial interest and pursuit in this highly technical and diverse profession. All of my professors, especially committee members, have added invaluable knowledge and skills to my repertoire over the years. It is in large part due to their passion for this profession that I am expertly prepared and enthusiastically ready to actively contribute to the next generation of micro/nano electronic technologies. Additionally, I may pursue a professorship in order to help share my own passion and knowledge to future generations. It would not have been possible to complete any of the experimental results in this work without the uncounted hours of help from the Semiconductor & Microsystems Fabrication Laboratory (SMFL) staff. Specifically I would like to thank Richard Battaglia, Thomas Grimsley, John Nash, David Yackoff, Scott Blondell, Prof. Karl Hirschman, Sean O’Brien, and Bruce Tolleson. They have always generously donated their time, knowledge, and expertise. This work would have been relegated to the realms of theory if it were not for them and the fabrication facility at RIT. Finally, my sanity throughout any year ebbed and flowed with my friends and family. I apologize to Paul Thomas, for spending so much time cursing out my computer while in the office or explaining how I “hate” X, Y, and Z. But you will never know how much that helped. Furthermore, game nights with Paul and Athena, Andy, and Marybeth were/are always welcome. Finally, beating up my body while mountain biking (thanks Athena) always seems to heal my mental state. And that is largely due to riding with Paul, Athena, Josh, Ben, Shone, Marybeth, John, Ryan, Scott, Katie, Carrie, Chelse, and everyone else I’ve met on the trails. Though we are separated by 1 small continent… let’s peddle! iv TABLE OF CONTENTS List of Tables ................................................................................................................................ viii List of Figures ................................................................................................................................. ix List of Abbreviations .................................................................................................................... xvi List of Variable ........................................................................................................................... xviii 1. Introduction and Motivation ...................................................................................................... 1 1.1. Introduction ....................................................................................................................