Abstract
The invention relates to a semiconductor device and a manufacturing method thereof. The semiconductor device includes: a substrate; a first nitride semiconductor layer provided on the substrate; and a second nitride semiconductor layer provided on the first nitride semiconductor layer and having a band gap larger than a band gap of the first nitride semiconductor layer. The semiconductor device further includes a first gate conductor disposed on the 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 a second region of the second nitride semiconductor layer, where the first region is laterally spaced apart from the second region.