Study on simultaneous formation of ohmic contacts on p- and n- type 4H-SiC using Ni/Ti/Al ternary system

In order to simplify the fabrication process of silicon carbide power MOSFETs (metal oxide semiconductor field effect transistors), the issue of the simultaneous formation process of ohmic contacts to both the p-well and n-source regions of the SiC devices using same contact materials and one step annealing needs to be addressed. In this study, Ni/Ti/Al ohmic contacts to p- and n-type 4H-SiC with different Ni thicknesses in different annealing conditions were fabricated and characterized, and the Ni (80 nm)/Ti (30 nm)/Al (80 nm) combination succeeded in forming low specific contact resistances (SCRs) of 4.2×10^-5 Ω cm² and 7.8×10^-5 Ω cm² for p- and n-type SiC, respectively, after annealing at 950 μC for 5 min.