  Device based on GaN have great potential for high power switching
applications due to its high breakdown field and high electron mobility. In
this work, we present the device design of a vertical GaN-on-GaN PN power diode
using high dielectric constant (high-k) dielectrics for electrical field
management and high breakdown voltages, in together with guard-rings and a
field plate. The fabricated diodes with a 57 um thick drift layer demonstrated
a breakdown voltage of 7.86 kV on a bulk GaN substrate. The device has an
on-resistance of 2.8 mohm.cm2 and a Baliga figure of merit of 22 GW/cm2.
