Improved Thermal Stability Observed in Ni-Based Ohmic Contacts to n-Type SiC for High-Temperature Applications

The high-temperature stability of a Pt/TaSi2/Ni/SiC ohmic contact metallization scheme was characterized using a combination of current-voltage measurements, Auger electron spectroscopy, and transmission electron microscopy imaging and associated analytical techniques. Increasing the thicknesses of the Pt and TaSi2 layers promoted electrical stability of the contacts, which remained ohmic at 600A degrees C in air for the extent of heat treatment; the specific contact resistance showed only a gradual increase from an initial value of 5.2 x 10(-5) Omega cm(2). We observed a continuous silicon oxide layer in the thinner contact structures, which failed after 36 h of heating. Meanwhile, thicker contacts with enhanced stability contained a much lower oxygen concentration that was distributed across the contact layers, precluding the formation of an electrically insulating contact structure.
The original publication is available at www.springerlink.com:Ariel Virshup, Fang Liu, Dorothy Lukco, Kristina Buchholt, Anita Lloyd Spetz and Lisa M Porter, Improved Thermal Stability Observed in Ni-Based Ohmic Contacts to n-Type SiC for High-Temperature Applications, 2011, JOURNAL OF ELECTRONIC MATERIALS, (40), 4, 400-405.http://dx.doi.org/10.1007/s11664-010-1449-0Copyright: Springer Science Business Mediahttp://www.springerlink.com