Solid state reaction of ruthenium with silicon carbide, and the implications for its use as a Schottky contact for high temperature operating Schottky diodes

A thin film of ruthenium was deposited on n-type-4-hexagonal-silicon-carbide (4H-SiC) so as to study the interface behaviour of the ruthenium Schottky contact with silicon carbide. Ruthenium (Ru) Schottky diode dots were also fabricated by deposition of ruthenium on n-type-4H-SiC which had nickel as a back ohmic contact. The Ru-4H-SiC Schottky barrier diodes (SBDs) and thin films were both annealed isochronally in a vacuum furnace at various temperatures. Rutherford-backscattering-spectrometry analysis of the thin film sample showed evidence of formation of ruthenium silicide (Ru2Si3) and diffusion of ruthenium into silicon carbide at annealing temperatures of 700 °C and 600 °C respectively. Raman analysis of the sample that was annealed in a vacuum at 1000 °C showed evidence of the formation of graphite, and Ru2Si3. Despite the occurrence of the chemical reactions and diffusion of ruthenium into 4H-SiC, the SBDs were operationally stable up to the final annealing temperature of 1000 °C.