2.8 kV Avalanche in Vertical GaN PN Diode Utilizing Field Plate on Hydrogen Passivated P-Layer

A novel edge termination method resulting in an avalanche-capable 2.8 kV vertical gallium nitride (GaN) pn diode is reported. A low transition temperature spin-on-glass (SOG) based field plate (FP) was deposited on top of the hydrogen-plasma passivated p GaN layer to achieve better electric field management. The hydrogen plasma treatment along with the field plate offered an edge termination without mesa etch that was able to mitigate the peak electric fields in the diodes. Avalanche was confirmed by the positive temperature coefficient of the breakdown voltage. Without the field plate, the breakdown voltage was recorded between 1.3 to 2.1 kV, without an avalanche behavior. The fabricated diodes exhibited a good rectifying behavior with an on-off ratio of <inline-formula> <tex-math notation="LaTeX">$10^{{9}}$ </tex-math></inline-formula> and a specific resistance of 1.65 <inline-formula> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula>cm². This work demonstrated the avalanche capability with the combination of FP and hydrogen-plasma based termination in GaN vertical pn diodes, showing a high figure-of-merit of 4.8 GW/cm².