Event
ECE Colloquium Series - Uttam Singisetti, University of Buffalo
Friday, April 18, 2025
3:30 p.m.-4:30 p.m.
Jeong H. Kim Engineering Building, Room 1110
Darcy Long
301 405 3114
dlong123@umd.edu
Speaker: Uttam Singisetti, Professor, University of Buffalo
Title: Ultrawide bandgap semiconductors: A new frontier in semiconductor microelectronics
Abstract: Semiconductor microelectronics plays a vital role in the current world impacting every aspect of human life including world economy and geo-politics. Ultrawide bandgap (UWBG) semiconductors with bandgaps > 4 times the silicon bandgap has recently emerged as a new class of materials for next generation power, 6G communication, quantum, AI datacenter applications. Several UWBG semiconductors ( Ga2O3, AlGaN-AlN, diamond, c-BN) are currently under investigation. Each of them provides both advantages and severe challenges, making it an exciting area of research. This talk will discuss the progress and challenges of gallium oxide high voltage devices and electron transport studies in AlGaN alloys.
The monoclinic b-gallium oxide (Ga2O3) (bandgap 4.8 eV) has garnered a lot of interest and the Ga2O3 device research has progressed at an incredible pace with reports of MOSFETs and diodes achieving 10 kV breakdown voltages. This progress has been underpinned by the high critical electric field, good electron mobility, multiple shallow donors, availability of large area substrates and growth of high-quality epitaxial films. This talk will present the most recent advances in gallium oxide devices. We will present the lateral MOSFETs with improved field plate design and beyond-kV breakdown and an innovative trench MOSFET for grid applications. We will discuss the ingenious ways to overcome the challenges; lack of p-doping and low thermal conductivity.
In the second part, I will talk about the first-principles calculations of the electron transport properties in AlGaN alloy systems. The lack of translational symmetry in the random alloys creates enormous challenges in these calculations using traditional approaches. A super cell based effective band structure and effective phonon dispersion is used to get phonon limited mobility. This study increases the accuracy of the performance predictions especially for high-temperature applications.
Finally, I conclude with the vision for UWBG semiconductor research, which provides an opportunity to advance knowledge across a broad range of science and engineering disciplines.
Bio: Dr. Uttam Singisetti is a Professor of Electrical Engineering at the University at Buffalo (UB). He received his PhD in Electrical and Computer Engineering from the University of California, Santa Barbara in 2009. He received MS degree from Arizona State University in 2004 and BS degree from the Indian Institute of Technology, Madras in 2001. He joined the EE department at UB in Fall 2011 and was promoted to Associate Professor in 2017 and full Professor in 2021. His research interests are in the areas of low-power devices for logic and memory; III-N based THz devices and next generation wide and ultra-wide bandgap materials and devices. At UB, he conducted pioneering fundamental work in understanding the low field and high field transport in Ga2O3 and demonstrated highest performance high voltage and RF devices. He is a recipient of Senior Researcher of the Year (2019-2020) award and UB Exceptional Scholar: Sustained Achievement Award in 2024. He has co-authored more than 150 publications in peer reviewed journals and conference proceedings with > 4700 citations. He is a Senior Member of the IEEE Electron Device Society. He served on the technical program committee of the IEEE Device Research Conference and on the IEEE EDS Technical Committee on Compound Semiconductor Devices and Circuits. He was Chair of a successful GOX2023 conference in 2023. He has served as Guest Editors in several journals including IEEE Transactions on Power Electronics, Scientific Reports and APL Materials.
