Solid State Reaction of Ruthenium with 6H-SiC Under Vacuum Annealing and the Impact on the Electrical Performance of its Schottky Contact for High Temperature Operating SiC-Based Diodes

Abstract

Thin films and Schottky diodes dots of ruthenium (Ru) on bulk-grown n-type-6-hexagonalsilicon carbide (6H-SiC) were annealed isochronally in a vacuum furnace at temperatures ranging from 500 -1000 o C. Rutherford backscattering spectroscopy analysis of the thin films showed formation of ruthenium silicide (Ru 2 Si 3 ) at 800 o C,while diffusion of Ru into 6H-SiC commenced at 800 o C . Raman analysis of the thin films annealed at 1000 o C showed clear D and G carbon peaks which was evidence of formation of graphite . At this annealing temperature the Schottky contact was observed to convert to an ohmic contact, as evidenced by the linearity of current-voltage characteristic , thereby rendering the diode unusable. The transformation from Schottky contact to ohmic contact is attributed to graphite formation at the interface.