Low Resistance Ohmic Contact Formation on 4H-SiC C-Face with NbNi Silicidation Using Nanosecond Laser Annealing
Non-equilibrium laser silicidations for low-resistance ohmic contact to 4H-SiC C-face with carbon-interstitial type metal, Nb was demonstrated. In a conventional nickel silicide (NiSi) electrode on SiC, a carbon agglomeration at the silicide/SiC interface occurs, and constant resistance between NiSi and SiC substrate becomes larger. For suppressing the carbon agglomeration, in this research, nanoseconds non-equilibrium laser annealing was introduced, and also carbon-interstitial type metal Nb to form metal carbides was introduced. Ni/Nb/SiC multilayer contact and NbNi mixed contact were formed on C-face side of 4H-SiC wafers. Electrical contact properties were investigated after 45 nanoseconds pulse laser annealing in N2 ambient. As the result, at the NbNi mixed contact, specific contact resistance of 2.4×10-4 Ωcm2 was realized.