In this abstract the development of vertical power transistors utilizing bulk GaN substrates with breakdown voltages of 5000V or higher, normally-off operation, and a drain current rating of 1A is proposed. These devices will feature vertical current flow, a threshold voltage of >2V, minimal to no dynamic on-resistance (such that Rac/Roc 50%. This Phase II proposal is a continuation of the work done in the Phase I effort.
Benefit: GaN devices fabricated on bulk GaN substrates have very low specific on-resistance compared to the similar breakdown voltage rated devices made on Silicon or SiC. As a result small device sizes are possible with bulk GaN which produce very small device capacitances. This allows power electronics applications to operate at much higher switching frequencies than applications using Si or SiC devices. Additionally the vertical nature of the devices allows for arbitrarily thick epi layers that translate to high breakdown voltage devices exceeding 5000V. The low defect density of bulk GaN substrates leads to high yielding, high reliability devices that can operate at very high temperatures. All of these factors combined lead to a reduced system size and cost, increased system reliability, reduced use of rare-earth metals and reduced cooling needs in high power applications. Potential applications are high efficiency, extremely high power density solar inverters and wind power converters, traction motor drives for hybrid vehicles, ship propulsion, solid-state transformers for grid connectivity, high temperature and reliability down-hole applications, etc,
Keywords: High-yielding, transistors, reliable, Power, vertical, Density , normally-off, GaN, defects
