Journal of Vacuum Science & Technology A, Vol.21, No.4, 1510-1514, 2003
Electrical contact behavior of Ni/C60/4H-SiC structures
A C60 interfacial layer between a Ni film and SiC improves the Ohmic contact properties significantly. The C60 film is deposited by the Langmuir-Blodgett method prior to the Ni film deposition on SiC using dc sputtering. High quality Ohmic contacts of Ni/C60/4H-SiC are formed after annealing at 800 degreesC in Ar for 2 h with a specific contact resistivity of 1.17 x 10(-6) Omega cm(2) on SiC with a doping concentration of 1.8 x 10(19) cm(-3). Raman spectra reveal that Ohmic contacts are formed after C60 is decomposed and converted to graphitic states. The formation of Ohmic contacts and the graphitic structures in the annealed film of Ni/C60/SiC are similar to that of Ni/C/SiC, for which the Ni catalytic graphitization effects play the determining role in forming Ohmic contacts on SiC., Scanning electron microscopy images show a direct relationship between the graphitized morphological features on the films and Ohmic contact behavior. (C) 2003 American Vacuum Society.