Abstract
The present disclosure relates to a semiconductor device and a fabrication method thereof. The semiconductor device includes a substrate, a first nitride semiconductor layer disposed on the substrate, a second nitride semiconductor layer disposed on the first nitride semiconductor layer and having a bandgap greater than that of the first nitride semiconductor layer. The semiconductor device further includes a first gate conductor disposed on a first region of the second nitride semiconductor layer, a passivation layer covering the first gate conductor, and a second gate conductor disposed on the passivation layer and on a second region of the second nitride semiconductor layer, wherein the first region is laterally spaced apart from the second region.