High-Temperature Ultra-Wide Bandgap Gallium Oxide Power Module

This NSF project aims to address the knowledge gaps and challenges that are presently limiting the advancement of high-temperature, high-density power electronics. High-temperature power electronics can increase the power density of transportation systems by reducing the size and weight of the cooling system, and enabling the power converter to be placed in strategic locations with high ambient temperatures, such as in close proximity to the engine or motor.

However, higher temperatures degrade the performance and reliability of present power electronics components. This project aims to overcome these challenges and develop a high-temperature gallium oxide power module. Gallium oxide is an ultra-wide-bandgap semiconductor that is emerging as a viable candidate for high-temperature power electronics due to its advantageous material properties.

The intellectual merits of the project include understanding of semiconductor device and package electro-thermal interactions, solutions for high-temperature package encapsulants and semiconductor device gate dielectrics, and strategies for thermal management. The broader impacts of the project include insight into the possibilities and challenges for gallium-oxide-based power electronics, and advancements in high-temperature packaging, which could allow for more-efficient and higher-density electric transportation and harsh-environment systems.

Other broader impacts of the project include undergraduate and graduate education on power electronics packaging and ultra-wide-bandgap semiconductors, and diversity and inclusion activities, such as hands-on workshops, laboratory tours, and demonstrations for women and underrepresented minorities.

Extreme temperatures challenge the limits of silicon power semiconductors, and diminish the performance benefits of wide-bandgap devices. While gallium oxide is a promising alternative due to its superior thermal stability, it has low thermal conductivity, which creates additional challenges for the package and thermal management system. Another major challenge is the reliability of the power electronics package under high temperature conditions.

In particular, a key limitation for high-temperature power modules is the encapsulation. The encapsulation provides essential electrical insulation, as well as corrosion resistance and protection. Traditional polymeric encapsulants degrade rapidly at elevated temperatures.

This work aims to overcome these challenges through four main research goals: 1) to develop an electro-thermal, device-package co-design framework that will enable physical insights into the device-package interdependencies, and accelerate the design of power modules optimized for emerging power semiconductor devices; 2) to evaluate and apply new dielectric materials for use as the high-temperature power module encapsulant, and as the gate dielectric and passivation for the gallium oxide power device; 3) to explore innovative heat dissipation strategies at the device and package levels for improved thermal performance of gallium-oxide-based power modules; and 4) to demonstrate a high-temperature gallium oxide power module, and assess its electrical, thermal, and reliability characteristics. The knowledge gained from this work will illuminate the potential of gallium oxide power devices, and enable significant improvements in high-temperature packaging, which could facilitate major advancements in electric transportation and harsh environment applications.

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.