Interplay between Barrier Inhomogeneity and Interface States in Pt/n-GaN Schottky Barrier Diodes

Using current–voltage (I–V) and capacitance–voltage (C–V) measurements, the current transport and interface characteristics properties of Pt/n-GaN Schottky barrier diodes (SBDs) were investigated. The forward I–V analysis (300–425 K) showed barrier inhomogeneity, consisted of a double Gaussian distribution of barrier heights. C–V characteristics revealed significant frequency dispersion and negative capacitance, indicating a high interface state density (Dit). The distribution of Dit was quantified using four different methods such as Hill-Coleman, Terman, conductance, and forward I–V, which displayed the Dit values in the range of low-1012 to high-1013 eV−1 cm−2. In addition, C–V hysteresis analysis showed the presence of negatively charged traps at the Pt/n-GaN interface. These results indicate the non-ideal current transport in GaN SBDs by emphasizing the coupled effects of barrier inhomogeneity and interface states.