Gallium nitride semiconductor device with improved forward conduction

A gallium nitride based semiconductor diode, comprising:

• a substrate;
• a semiconductor body comprising a first GaN layer of a first conductivity type formed on the substrate and a second GaN layer of the first conductivity type formed on the first GaN layer, the second GaN layer being more lightly doped than the first GaN layer, the semiconductor body including a plurality of mesas projecting upwardly from a lower surface, the lower surface extending partially into the first GaN layer, each of the plurality of mesas including the second GaN layer and a portion of the first GaN layer;
• a first metal layer formed on an upper surface of the plurality of mesas for forming a Schottky junction with the second GaN layer;
• a second metal layer formed on the lower surface between the plurality of mesas for forming ohmic contacts to the first GaN layer;
• an insulating layer formed over the first and second metal layers;
• a first plurality of vias formed in the insulating layer to form openings to the first metal layer, the first plurality of vias being filled with a via metal;
• a second plurality of vias formed in the insulating layer between the plurality of mesas to form openings to the second metal layer, the second plurality of vias being filled with the via metal;
• a first metal pad formed in a third metal layer overlying the insulating layer and over in electrical contact with the first plurality of vias, the first metal pad forming an anode electrode;
• and
• a second metal pad formed overlying the insulating layer and in electrical contact with the second plurality of vias, the second metal pad forming a cathode electrode.