Ion-implanted triple-zone graded junction termination extension for vertical GaN p-n diodes

We demonstrate an ion-implanted triple-zone junction termination extension (JTE) for vertical GaN p-n diodes. Due to the spatial distribution of fixed charge in the triple-zone JTE structure, the peak electric fields at the contact metal edge and at the edge of the JTE are significantly reduced compared to conventional approaches. The forward and reverse characteristics of diodes with conventional single-zone JTE and the triple-zone JTE explored here have been studied and compared experimentally. GaN p-n diodes fabricated using the triple-zone JTE obtain an experimentally measured maximum breakdown voltage of 1.27 kV, appreciably higher than the 1.01 kV achieved using the single-zone JTE structure. The triple-zone JTE design also provides a wider window for fabrication processing and epitaxial wafer growth to achieve the high breakdown voltage compared to single-zone designs. The triple-zone JTE is promising for cost-effective fabrication of GaN power electronics.