Fabrication of 1.4-kV mesa-type p+–n diodes with avalanche breakdown and without forward degradation on high-quality 6H-SiC substrate

Using our own substrate growth and epitaxial growth techniques, we fabricated a 1.4-kV mesa-type 6H-SiC p+–n diode with an ideal avalanche breakdown and without forward degradation. The 6H-SiC substrates were grown on Lely crystals with no micropipes and only minimal defects. A p+–n junction was fabricated by chemical vapor deposition with p+/n− epitaxial films. We obtained 1.4-kV breakdown voltage, consistent with the ideal breakdown voltage calculated from the thickness and doping concentration of the drift layer. The application of 200-A/cm2 current stress in the forward direction produced no degradation, which is often observed with p–n diodes on normal substrates.