Ultra-wide Bandgap based High Voltage Electron Devices towards Grid Scale Applications

Abstract

Electricity has emerged as the most indispensable form of energy, playing a central role in powering modern society. Currently, electricity generation and consumption account for a significant 40% of the global energy demand, highlighting its critical importance in meeting the world’s energy needs. As the demand for efficient power conversion grows, wide bandgap (WBG) semiconductors such as SiC and GaN are revolutionizing energy conversion—GaN excelling in high-speed applications, while SiC dominates high-power systems. We are at a critical juncture where innovation in ultra-wide bandgap (UWBG) materials is enabling the next leap in power electronics technology – particularly for the grid scale systems. The key to unlocking their full potential lies in advanced electrostatic engineering strategies that optimize electric field management, a critical factor in preventing premature breakdown and enhancing power device efficiency.

In this seminar, I will present electrostatic engineering strategies for high-voltage devices using β-Ga₂O₃ – an UWBG material, focusing on innovative edge termination and field management techniques. These strategies aim to improve device performance and efficiency. The discussion will focus on the demonstration of dielectric superjunction devices that incorporate high-permittivity dielectrics with β-Ga₂O₃, enabling us to surpass the material’s theoretical unipolar figure of merit. I will highlight the development of vertical power devices that achieve high voltage (>1 kV) and high current (>1 A) operation through the use of extreme-permittivity dielectric REduced SURface Field (RESURF) structures. The seminar will also cover the optimization of efficiency and power losses—both static and switching—in these devices. Further, I will showcase my work on kilovolt class β-Ga₂O₃–based vertical FinFETs with advanced field management strategies delivering record high Power Figure of Merit (PFOM). Beyond device architecture, I will discuss advancements in material engineering, including in-situ MOCVD deposition of high-quality Al₂O₃ on β-Ga₂O₃. This approach ensures a pristine dielectric/semiconductor interface, leading to superior breakdown strength and reliability compared to conventional gate dielectric deposition methods. These breakthroughs collectively push the boundaries of β-Ga₂O₃ power electronics, paving the way for next-generation, energy-efficient, and high-performance power devices.

Bio

Saurav Roy received his B.Tech in Electronics and Communications Engineering from National Institute of Technology Silchar, India and M.Tech in Electronics and Electrical Engineering from Indian Institute of Technology Guwahati, India. He earned his Ph.D. in December 2024 from the Materials department at the University of California, Santa Barbara (UCSB). After graduation he joined Materials department as a post-doctoral researcher. Saurav has received the Institute of Energy Efficiency (IEE) Excellence in Research Fellowship for the year 2022-2023 and was honored with the Outstanding Graduate Student Research Achievement Award, 2022-2023 and 2023-2024 at the 9^th and 10^th Annual SSLEEC Annual Review conference held at UCSB.

His current research interests encompass the design and fabrication of devices based on wide and ultra-wide bandgap materials for both power and radio frequency applications and epitaxy of ultra-wide bandgap materials. His work involves the device design and fabrication of β-Ga₂O₃-based power devices, as well as TCAD simulation, analytical modeling of novel devices, and metal-organic chemical vapor deposition (MOCVD) growth and electrical characterization. Notably, he has developed and demonstrated dielectric superjunction devices in β-Ga₂O₃ and in-situ dielectric deposition on β-Ga₂O₃ using MOCVD.