Structural and bonding properties of carbon nitride films prepared by dc magnetron sputtering

Abstract

Amorphous carbon nitride (CN x ) films have been deposited onto Si(100) substrates by reactive sputtering of a graphite target in a pure N 2 ambient. A modified cylindrical DC magnetron plasma was used as a sputter deposition source and the effects of substrate DC self-bias voltage caused by RF bias on film properties were investigated. X-ray photoelectron spectroscopy (XPS) spectra of N 1s and C 1s electron confirmed the existence of multiple bonding states for carbon and nitrogen (sp 2 and sp 3) in the film. Fourier transform infrared (FTIR) spectroscopy studies showed a systematic variation in spectra by a DC self-bias voltage. Raman spectra revealed two peaks corresponding to G band (1580 cm −1) and D band (1370 cm −1). The ratio of integrated intensities of D and G band ( I D/ I G) increased with DC self-bias voltage, suggesting increased disorder by the ion bombardment on growing film. Variation in the morphology of CN x films deposited at different bias voltage was examined by scanning electron microscopy (SEM).