DC electrical conductivity study of amorphous carbon nitride films prepared by reactive RF magnetron sputtering

Abstract

The effects of chemical bonding states on the electrical properties of hydrogen-free amorphous carbon nitride (a-CNx) films were reported. a-CNx films were prepared by reactive RF magnetron sputtering at various deposition temperatures. The electrical conductivity of the a-CNx films increased with increasing deposition temperature because of the predominant sp2C–C bonding sites. Their conductivity increased by almost one order of magnitude with a 25% decrease in the fraction of the N-sp3C bonding state. It was found that the fraction of the N-sp2C bonding state strongly contributed to the increase in the electrical conductivity. Nitrogen incorporation led to an increase in the sp3C–C bonding fraction in the films; as a result, the conductivity of the a-CNx films was found to be lower than that of the a-C films deposited under the same conditions.