1200-V Fully Vertical GaN-on-Silicon p-i-n Diodes With Avalanche Capability and High On-State Current Above 10 A

We report on fully vertical gallium nitride (GaN)-on-silicon (Si) p-i-n diodes delivering above 1200-V soft breakdown voltage (BV). Temperature dependence measurements indicate avalanche breakdown capability reflecting the high-quality processing and epitaxy growth. The ON-state characteristics of the fabricated vertical p-i-n diodes reveal on-resistances ranging from 0.48 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula>cm2 for small anode to 1.7 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula>cm2 for large anode diameters (i.e., 1 mm). The ON-state resistance increase is attributed to the thermal dissipation issues. Nevertheless, the large devices exhibit high ON-state current close to 12 A owing to an optimized process, including a deep mesa etch as edge terminations and thick Cu layer for heat sink on the backside enabled by a polyimide passivation that strengthen the mechanical robustness of the membranes. To the best of our knowledge, this represents the first demonstration of fully vertical 1200-V GaN-based devices grown on Si substrates with high-current operation above 10 A, corresponding to a Baliga figure of merit (BFOM) of 3 GW/cm2.