Diffusion barriers on titanium-based ohmic contact structures on SiC

Silicon carbide is a very promising semiconductor material for high temperature applications and it can also be expected to become the material of choice for power semiconductor devices. One of the requirements for a working semiconductor device is the availability of a low resistance and thermally stable ohmic contact. Contact systems on n-6H-SiC using titanium-based contact materials (Ti/sub 3/SiC/sub 2/, TiSi/sub 2/, TiC), diffusion barriers (Pd, Ti, TiC, TiCN, W) and top metallizations (Al, Au, Pd) were investigated. Best results were obtained using the SiC-Ti/sub 3/SiC/sub 2/-Pd-Au contact layer structure, which is morphologically and electrically stable for up to 90 hours at 600/spl deg/C and exhibits good ohmic behaviour.