HighTemperature Ohmic and Schottky Contacts to NType 6HSiC Using Nickel

We report specific contact resistances measured at elevated temperatures for Ni ohmic contacts to 6H-SiC. The specific contact resistances were measured with the linear transmission line method at both room temperature and at 773 K and yielded values > 5 x 10^-6 ?>-cm² at both temperatures. The trend shows a decreasing contact resistance at higher temperatures. The annealed metal film is a nickel silicide with substantial mixing of C throughout the silicide layer. Also reported are the results of I-V and C-V barrier height measurements for Ni Schottky contacts to 6H-SiC. Current-voltage barrier heights as high as 1.2 eV have been measured, and the contacts show good electrical and physical stability following long-term anneals at 573 K in a vacuum ambient of 10^-6 torr. These ohmic and Schottky contacts have been developed by the CCDS in collaboration with the Air Force and the Westinghouse Electric Corporation, and transfer of our contact technology to the Westinghouse Science and Technology is now complete.