Ni–Al ohmic contact to p-type 4H-SiC

Investigations on Ni/Al alloys to form ohmic contacts to p-type 4H-SiC are presented in this paper. Different ratios of Ni/Al were examined. Rapid thermal annealing was performed in argon atmosphere at 400 ∘C for 1 min, followed by an annealing at 1000 ∘C for 2 min. In order to extract the specific contact resistance, TLM test structures were fabricated. A specific contact resistance of 3×10−5 Ω cm2 was obtained reproducibly on Al2+ implanted p-type layers, having a doping concentration of 1×1019 cm−3. The lowest specific contact resistance value measured amounts to 8×10−6 Ω cm2.