Effective Selective Area Growth
Electricity generation currently accounts for ~40% of primary energy consumption in the U.S. and continues to be the fastest growing form of end-use energy. Power electronics are responsible for controlling and converting electrical power to provide optimal conditions for transmission, distribution, and load-side consumption. By 2030 as much as 80% of all electricity could pass through some form of power electronics. Applications for power electronics are widespread and include uses in power supplies, motor drives, grid applications, data centers, and distributed energy resources. Today, most power electronics are based on silicon semiconductor devices that have reached their efficiency limits at high power and frequency, due to the material limitations of silicon. Wide-bandgap (WBG) semiconductors such as gallium nitride (GaN) have superior electrical conductivity, breakdown properties, and switching speed. This allows for power converters with much improved efficiencies over silicon - while also dramatically reducing system size, weight, and form factor. Power semiconductor devices overwhelmingly use vertical architectures to realize high breakdown voltage (>1200V) and current levels, without having to enlarge chip size. The vertical architectures require the ability to add specific impurities to selected regions of a semiconductor to produce negative (n-type) and positive (p-type) electrical conduction, a process called doping. Currently, no doping process exists to form selective p-type regions in GaN. This is the major barrier to realization of GaN based vertical power electronic devices. The development of a selective p-type doping process will enable vertical GaN device architectures and unlock the potential of using the WBG semiconductor GaN in power electronics.
Project Innovation + Advantages:
Arizona State University (ASU) proposes a comprehensive project to advance fundamental knowledge in the selective area doping of GaN using selective regrowth of gallium nitride (GaN) materials. This will lead to the development of high-performance GaN vertical power transistors. The ASU team aims to develop a better mechanistic understanding of these fundamental materials issues, by focusing on three broad areas. First, they will use powerful characterization methods to study fundamental materials properties such as defects, surface states, and investigate possible materials degradation mechanisms. Next, they will develop innovative epitaxial growth and fabrication processes such as Atomic Layer Etching and novel surface passivations, to tackle the materials engineering challenges related to selective area doping for GaN p-n junctions. Finally, they will apply their research to demonstrate randomly placed, reliable, contactable p-n junctions for GaN vertical power devices. If successful, this project will provide a path towards high efficiency, high power, small form factor, and high thermal performance GaN vertical power devices.
If successful, PNDIODES projects will enable further development of a new class of power converters suitable in a broad range of application areas including automotive, industrial, residential, transportation (rail & ship), aerospace, and utilities.