High Breakdown Voltage and High Current Injection Vertical GaN-on-GaN p-n Diodes With Extremely Low On-Resistance Fabricated on Ammonothermally Grown Bulk GaN Substrates

In this work, we report fabrication and characterization of high breakdown voltage and high current injection vertical gallium nitride (GaN)-on-GaN p-n diodes with an etched mesa structure with guard rings termination on ammonothermally grown bulk GaN substrates. Bright electroluminescence from active region under forward bias was observed with high intensity near band edge emission and low intensity defect and unintentional impurities-related bands. Fabricated devices were characterized by a high breakdown voltage up to 1940 V, a high on/off current ratio over
$10^{{13}}$
, a high current density above 10 kA/cm2, and an extremely low ON-resistance below 0.1
$\text{m}\Omega $
cm2 under high current injection.