Role of titanium in Ti/Ni ohmic contact on n-type 6H-SiC
A set of Ti/Ni metallizations with different thickness of the underlying titanium layer was prepared on 6H-SiC together with structures that contained only pure Ti and Ni. Samples were gradually annealed at 7501150C. Structures Ti(2)/Ni(50) and Ti(100)/Ni(50) showed the lowest contact resistivity, 210?4?cm2 in both cases. For the Ti(2)/Ni(50) structure, low contact resistivity was reached most likely due to reduction of surface oxides on SiC by the thin titanium layer. In the Ti(100)/Ni(50) structure, the titanium layer prevents diffusion of nickel towards SiC and there is a layer containing mainly TiC at the interface with silicon carbide.
titanium ohmic contact nickel silicon carbide sputtering xps analysis