Abstract: Ohmic contact formation inclusive of Carbon films on 4H and 6H n-type Silicon Carbide is disclosed. Contact formation includes an initial RF sputtering to produce an amorphous Carbon film with the sp2/sp3 Carbon ratio of about 1.0 measured by X-ray photoelectron spectroscopy. This Carbon film gradually evolves from sp3 to sp2 structures of high sp2 content during an annealing at temperatures ranging from 600° C. to 1350° C. depending on the substrate doping levels, between 1016 and 1019, employed. Formation of sp2 Carbon is accelerated by the presence of metal and gaseous catalytic agents including for example nickel and argon. The sp2 Carbon structures consist especially of nano-size graphitic flakes and also of amorphous aromatic-like Carbon structures, and polyene-like Carbon structures, as are revealed by Raman spectroscopy. Ohmic contact is achieved when a sufficient amount of nano-graphitic flakes are formed at the selected annealing temperature.

Abstract: Ohmic contact formation on p-type Silicon Carbide is disclosed. The formed contact includes an initial amorphous Carbon film layer converted to graphitic sp2 Carbon during an elevated temperature annealing sequence. Decreased annealing sequence temperature, reduced Silicon Carbide doping concentration and reduced specific resistivity in the formed ohmic contact are achieved with respect to a conventional p-type Silicon Carbide ohmic contact. Addition of a Boron carbide layer covering the p-type Silicon Carbide along with the sp2 Carbon is also disclosed. Ohmic contact improvement with increased annealing temperature up to an optimum temperature near 1000° C. is included. Addition of several metals including Aluminum, the optimum metal identified, over the Carbon layer is also included; many other of the identified metals provide Schottky rather than the desired ohmic contacts, however.