CHEMICAL AND STRUCTURAL-ANALYSES OF THE TITANIUM NITRIDE/ALPHA (6H)-SILICON CARBIDE INTERFACE

Ion-assisted reactive evaporation (IARE) using low-energy (100 eV) nitrogen ions was employed to deposit TiN films onto the vicinal Si-terminated (0001) face of alpha(6H)-SiC single crystals at 350-degrees-C in an ultrahigh vacuum chamber operated at a working pressure of 2 X 10(-4) Torr. The initial exposure of the SiC surface to nitrogen ions for a 2-min period resulted in Si-N bonding. This exposure was also an important step in attaining ohmic contact properties at low temperature, and the formation of a thin (almost-equal-to 5-15 angstrom) amorphous layer at the interface. The disorder was maintained after the deposition of 5 angstrom of TiN. The TiN contacts were ohmic after deposition; they showed little change in microstructural or electrical properties after annealing at 450, 550, and 600-degrees-C for 15-30 min. The results of this research indicate that a metal-insulator-semiconductor structure was responsible for obtaining the contact properties.