Abstract
Ultrahigh-voltage 4H-SiC mesa PiN diodes are fabricated and characterized. An original space-modulated two-zone junction termination extension (SM-two-zone JTE) has realized a laterally tapered profile of the JTE dose, which enlarged the tolerance to the deviation of effective JTE dose compared with a conventional two-zone JTE. We demonstrate a SiC PiN diode with a breakdown voltage of 21.7 kV (81% of the ideal breakdown voltage calculated from the epilayer structure), which is the highest breakdown voltage among any semiconductor devices ever reported.