Schottky barrier formation on rf-plasma enhanced chemical vapour depositedhydrogenated amorphous carbon

This paper reports the fabrication and electrical characterization of sub-m icron metal contacts to thin films of hydrogenated amorphous carbon deposit ed by the r.f.-plasma enhanced chemical vapour deposition technique. The I- V characteristics of "large" area (diameter 0.5 mm) top metal contacts to a morphous carbon are consistent with bulk limited conduction by the Poole-Fr enkel mechanism. The I-V characteristics of sub-micron metal contacts, form ed at different locations on the same amorphous carbon film, range from sym metrical to highly asymmetrical with forward-to-reverse rectification ratio s up to three orders of magnitude. Asymmetrical I-V characteristics and a l inear C-2-V response confirm, for the first time, Schottky barrier formatio n at the metal/amorphous carbon interface. Spatial non-uniformity in the co mposition of the hydrogenated amorphous carbon surface is indicated, which mirrors bulk inhomogeneity. (C) 1998 Published by Elsevier Science S.A. All rights reserved.