Simulation Study of the Breakdown Performance for Vertical GaN PiN Diode with Mesa-terminals and Field-plate Structures

In this work, we have used Silvaco TCAD to study the electric-field profile of vertical GaN-based PiN diode mesa terminal structures when avalanche breakdown occurs at different etch depths, especially near the device edge. The negative angle mesa structures of vertical GaN-PiN diodes with different angles were also studied, and the surface electric-field and breakdown voltage at PN junction-depletion region interface were analysed. Finally, a vertical GaN-PiN diode structure with field-plate at an etching depth of T=0.5 was studied. The electric-field profile and breakdown voltage at the depletion region edge with a Si 3 N 4 passivation layer and a field-plate structure were analysed, as well as the negative angle (θ=40°) mesa and the field-plate structures.