Currently, up to 60% of consumed energy is related to electrical energy which undergoes a large amount of wastage in power electronics systems, and by 2030, it is expected that 80% of all electric power will flow through power electronics systems. Key to this wastage is the limited efficiency and scalability of power devices that are the building blocks of power conversion systems. For the projected compact high-power electronics, ultra-wide bandgap (UWBG) semiconductors, such as beta-phase of gallium oxide (β-Ga2O3), can be a viable candidate to enable significantly efficient, smaller, and faster power switches, replacing silicon. This collaborative project aims to develop a scientific base and engineering for robust multi-kV ampere class compact packaged UWBG <br/>β-Ga2O3 power devices by addressing existing challenges at both the device level and the packaging level. The integrated education plans will train the next generation of UWBG engineers and researchers to maintain the competitive vitality of the U.S. power electronics workforce in light of the trend towards high voltages, high power densities, and high temperatures. The project will also involve incoming first-year undergraduate students in this research program through the Clark Summer Research Program at the University of Texas at Dallas and the First Year Honors Mentor Program at Iowa State University.<br/><br/>This project will establish a comprehensive understanding of β-Ga2O3 devices under extreme fields, high temperatures, and defects, and perform a holistic improvement integrating material properties, device design, and packaging techniques. At the device level, the objectives are (i) robust high field and thermal management combining (ultra)high permittivity and high thermal conductivity dielectric, guard rings, and substrate thinning, (ii) Schottky barrier engineering with optimized contact configuration to enable high surface breakdown field, improved thermal stability, and low loss, and (iii) defect mitigation in large-area power devices through identifying defects in drift layers and interfaces, and coordinated process development. At the packaging level, this pioneering proposal will investigate and integrate two novel insulation materials and systems: (I) two particular high-temperature liquid dielectrics as pure and nanodielectric fluid forms, and (II) nonlinear field-dependent conductivity (FDC) materials, where (I) is proposed as a substitute for silicone gel in high voltage, high power UWBG β-Ga2O3 devices. For electric field control within the module, new insulation systems will be innovated by applying a combination of nonlinear FDC materials as layers on high electric stress regions, mentioned above in (II), and using geometrical techniques to reduce electric fields to control partial discharges. It is a highly coupled and interconnected device-packaging project where new packaging methods are tailored to the ampere-class multi-kV <br/>β-Ga2O3 device targeted in this project. Further, the packaging will be extended to the device level, where, for example, substrate thinning will be examined in combination with packaging techniques at the module level. As a result, the project will develop an electro-thermal, device-package codesign framework that allows physical insight into the device-package interdependencies and speeds up the design of power modules that maximize the potential of emerging UWBG power devices.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.