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This paper presents the structural, chemical and electronic properties of A1/Ni/ Al-layers evaporated on 4H silicon carbide and then annealed at 1000~ for 5 min. The structure was investigated before and after annealing by transmission electron spectroscopy from cross-sectional specimens. With x-ray photoelectron spectroscopy, both element distribution and bonding energies were followed during sputtering through the alloyed metal-semiconductor contact. Voids are found in both annealed Ni/4H-SiC and A]/Ni/A1/4H-SiC contact layers, though closer to the metal-semiconductor interface in the former case. The first aluminum-layer is believed to prevent voids to be formed at the interface and also to reduce the oxide on the semiconductor surface. The contact was found to be ohmic with a specific contact resistance Pc = 1.8 • 10 -5 ~2cm 2 which is more than three times lower Pc than for the ordinary Ni/4H-SiC contact prepared in the same way.

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