Design, fabrication and characterization of mesa combined with JTE termination for high-voltage 4H-SiC PiN diodes

Mesa combined with JTE termination structures for high-voltage 4H-SiC PiN diodes are designed, fabricated, and characterized in this paper. Designs based on simulation are performed to investigate the influence of the mesa shape on breakdown for SiC PiN diodes. It is found that a deeper mesa height and a smaller mesa angle contribute to a higher breakdown voltage owing to a smoother and more uniform surface electric field distribution. A maximum reverse blocking voltage of 3.8 kV and an on-state voltage drop of 3.4 V at 100 A/cm2 are obtained from the fabricated diodes with a mesa height of 2.1 μm and a mesa angle of 22°, corresponding to about 80% of a parallel plane breakdown voltage for the drift layer with a thickness of 30 μm. Additionally, the dependence of the breakdown voltage on the JTE length observed in the fabricated diodes shows a good agreement with the simulated results in the trend.