Plasma Analysis of a DC Sputtering Discharge in an N2/Ar atmosphere for the Deposition of Fullerene like Carbon Nitride

Fullerene like carbon nitride (CNx) is a nanostructured material consisting of bent and intersecting graphitic layers. It combines the unique properties of being hard and elastic at the same time, which results in a fracture though and compliant material. Homogeneous well-structured fullerene like CNx thin films are commonly grown by DC reactive magnetron sputtering of graphite in an N2/Ar mixture. The nitrogen content in the films is fairly constant, limited due to the formation of volatile CN species at the substrate surface. Even though the composition is similar the structure and properties of these films can be varied over a very wide range in a comparatively narrow process window. This suggests that beside C and N ions and atoms other species like CN clusters might play an important role during growth. Here direct effects as growth templates or nucleation sites should be considered.

Plasma analysis was carried out during this study in order to investigate the presence, number, and energy of clusters consisting of C and N and their possible effects upon the growing film. A number of techniques, such as spatially resolved wire and ion probe measurements and energy selective mass spectrometry were used to characterize the composition and energetic conditions of a N2/Ar DC sputtering plasma in front of a single graphite target, depending on discharge current, total pressure and gas composition.