Abstract Using atomic-force-microscopy investigations of the electrostatic system of the crystal surface of AuNi/ n – n ^+-GaN planar Schottky diodes, it is shown that the electron work function for the surface of metal Schottky contacts depends on their linear size (diameter D ). At D > 120 μm, the work function of the central contact region approaches the work function e φ_Au ≈ 5.40 eV of a continuous metallic gold film. A decrease in the diameter leads to a decrease in the work function to 5.34 eV at D = 120 μm, 5.21 eV at D = 40 μm, 5.18 eV at D = 10 μm, and 5.14 eV at D = 5 μm. The observed decrease in the work function with diameter is related to the increasing influence of the built-in periphery electrostatic field E _ l , which is determined by the area and perimeter of the Schottky contact. The fundamental differences between the thermodynamic and electrostatic systems of TiAlNiAu/ n ^+-GaN ohmic contacts, in contrast to analogous AuNi/ n -GaN Schottky systems, are indicative of the absence of a Schottky barrier in them and the decisive role of the thermionic transport of mobile carriers.
Исследование электростатической системы поверхности кристаллов AuNi/GaN диодов Шоттки методом зонда Кельвина атомно-силовой микроскопии