A semiconductor device includes a first active layer disposed over a substrate. The second active layer is disposed on the first active layer. The second active layer has a higher bandgap than the first active layer such that a two-dimensional electron gas layer arises between the first active layer and the second active layer. The first electrode establishes a Schottky junction with the second active layer. The first electrode includes a first electrode pad and a first series of fingers in electrical contact with the first electrode pad. The second electrode establishes an ohmic junction with the first active layer. The second electrode includes a second electrode pad and a second series of fingers in electrical contact with the second electrode pad. The first and second series of electrode fingers form an interdigitated pattern. The first electrode pad is located over the first and second series of electrode fingers.