Electrical and optical properties of CN[sub x](0≤x≤0.25) films deposited by reactive magnetron sputtering.

The electrical and optical properties of carbon-nitride CN[sub x] films (0≤x≤0.25) deposited by unbalanced reactive magnetron sputtering from a graphite target in mixed Ar/N[sub 2] discharges at a substrate temperature of 350 °C have been investigated. Pure C films exhibit a dark conductivity at room temperature of 25 Ω[sup -1] cm[sup -1], which grows up to 250 Ω[sup -1] cm[sup -1] for CN[sub x] films with N content of 20%. For CN[sub x] films, temperature-dependent conductivity measurements suggest that two electron conduction processes exist in the investigated temperature range 130<T<300 K. Under white-light illumination, photoconductivity is observed. The film optical properties obtained from spectroscopic ellipsometry measurements between 1.24 and 5 eV indicate a semimetallic behavior with a large amount of sp[sup 2] bonds in the material. The measured electrical and optical properties of the films are related to the apparent film microstructure and bonding nature. Electron microscopy show that the addition of N[sub 2] in an Ar discharge leads to a transformation from amorphous to a fullerene-like microstructure consisting of curved, frequently intersecting, and highly in-plane oriented basal lattice planes. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]