Semiconductor device with field plates

A semiconductor device comprising:

• source fingers and drain fingers provided on an active region of a nitride semiconductor layer alternately;
• gate fingers provided between the source fingers and the drain fingers and having a side edge and a distal edge;
• a first insulation film provided on the nitride semiconductor layer and covers a top face, the side edge and the distal edge of the gate fingers;
• field plates provided on the first insulation film between the gate fingers and the drain fingers, a minimum distance between the side face of the first insulation film located on the side edge of the gate fingers and the field plate being at least 100 nm;
• and
• field plate interconnections provided on the first insulation film and located outside of the active region and electrically connected with the source fingers and the field plates, a minimum distance between the side face of the first insulation film located on the distal edge of the gate fingers and the field plate interconnections being at least 100 nm.