Characterization of Ohmic Ni/Ti/Al and Ni Contacts to 4H-SiC from -40°C to 500°C

Extreme temperature measurements of Ni/Ti/Al contacts to p-type SiC (N a = 1∙10 18 cm -3 ), with a specific contact resistivity ρ c = 6.75∙10 -4 Ωcm 2 at 25 °C, showed a five time increase of the specific contact resistivity at -40 °C (ρ c = 3.16∙10 -3 Ωcm 2 ), and a reduction by almost a factor 10 at 500 °C (ρ c = 7.49∙10 -5 Ωcm 2 ). The same response of ρ c to temperature was seen for contacts on lower doped epitaxial layer. Also N-type nickel contacts improved with higher operational temperature but with a considerably smaller variation over the same temperature interval. No degradation of the performance was seen to either the Ni/Ti/Al or the Ni contacts due to the high temperature measurements.