Barrier height analysis of metal/4H-SiC Schottky contacts

Determination of barrier heights in Au/, Ni/, and Ti/4H-SiC Schottky structures was carried out in detail. The barrier heights were measured by current-voltage, capacitance-voltage characteristics, and internal photoemission spectroscopy. From internal photoemission spectroscopy, the most reliable Schottky barrier heights were obtained. There existed the dependence of barrier height on surface polarity of 4H-SiC (Si- and C-face). The barrier heights were 1.81 V (Au), 1.69 V (Ni), and 1.09 V (Ti) for Si-face, and 2.07 V (Au), 1.87 V (Ni), and 1.25 V (Ti) for C-face, so that the values for C-face are 0.2 similar to 0.3 V higher than those for Si-face. Besides, the ''barrier height pinning'' was not observed in metal/4H-SiC Schottky structures.