Electrical characteristics of nitrogen incorporated hydrogenated amorphous carbon

Nitrogen incorporation into hydrogenated amorphous carbon (a-C:H) films has recently attracted a wide range of interest due to its contribution in reducing film stress and improving field emission properties. In this work we characterize the electrical properties of nitrogen containing a-C:H films. The a-C:H films were prepared by plasma, enhanced, chemical vapor deposition in an acetylene (C2H2) environment, with a range of bias voltages. Nitrogen incorporation was achieved by exposing the films to an atomic nitrogen flux from a rf plasma with up to 40% dissociation and atomic nitrogen fluxes of up to 0.85 X 10(18) atoms s(-1). Raman results indicate that the doping process is accompanied by some structural changes seen by the G-band peak shifts. X-ray photoelectron spectroscopy spectra suggest that the dopant levels exceed those previously reported. Capacitance probe and I-V techniques showed a decrease in contact potential difference and density of states for doped films, indicating a rise in the Fermi level. (C) 2001 American Vacuum Society.