Patent ID: 8629525
Filing Date: 2014-01-14
Classification: H01L

Abstract:
1. A Schottky diode comprising: a substrate; a first nitride-based semiconductor layer disposed atop the substrate, the first nitride-based semiconductor layer being of a first conductivity type and having a first doping concentration; a second nitride-based semiconductor layer of the first conductivity type disposed atop a portion of the first nitride-based semiconductor layer, the second nitride-based semiconductor layer having a top planar surface, first and second sidewalls, and a second doping concentration lower than the first doping concentration, first and second planar surfaces of the first nitride-based semiconductor layer being exposed adjacent the first and second sidewalls, respectively; a first Schottky contact metal layer having a first metal work function disposed on the top planar surface entirely over the second nitride-based semiconductor layer of the first conductivity type, a first Schottky junction with a first barrier height being formed between the first Schottky contact metal layer and the second nitride-based semiconductor layer; a second Schottky contact metal layer having a second metal work function disposed atop of and laterally surrounding the first Schottky contact metal layer, the second metal work function being higher than the first metal work function, a second Schottky junction with a second barrier height being formed between laterally surrounding portions of the second Schottky contact metal layer and the second nitride-based semiconductor layer; a metal layer disposed on the first and second planar surfaces that forms an ohmic contact with the first nitride-based semiconductor layer.