Formation and interface analysis of Ti/Ni/Ti/Au ohmic contacts on n-type 6H-SiC

Abstract

We present the results of Ti/Ni/Ti/Au multilayer ohmic contacts on n-type 6H-SiC and their interface analysis. The as-deposited contacts show rectifying behavior and, with the increase in annealing temperature, they gradually transform to high-quality ohmic contacts exhibiting linear current-voltage characteristics. The interface evolution was analyzed through glancing angle X-ray diffraction, Auger electron spectroscopy, and atomic force microscopy. The TiSi2 and Ni2Si formed at the interfaces during the low-temperature annealing initiate the conversion from Schottky to ohmic behavior, while the increased Ni2Si formation at high-temperature annealing makes the perfect ohmic contacts. The results were interpreted through the thermodynamic reaction mechanisms.