Current collapse suppression in AlGaN/GaN HEMTs by means of slant field plates fabricated by multi-layer SiCN

•We report a new fabrication process to realize a slant field plate using a multi-layer SiCN film.•AlGaN/GaN HEMTs with several shapes of conventional and slant field plates are fabricated.•The current collapse of HEMTs with several shapes of field plates is compared experimentally.•The slant field plates suppress the current collapse more than the conventional field plates.

We report a new fabrication process to realize a slant field plate – a field plate in which the plate-to-channel distance gradually increases with the distance from the gate edge – using a multi-layer SiCN film. AlGaN/GaN HEMTs with several types of field plates are fabricated by this technique. The current collapse in the pulsed measurements is suppressed by the slant field plates more effectively than the conventional parallel-plate field plates as a result of the reduced electric field at the gate edge.