Determination of the structure of amorphous nitrogenated carbon films by combined Raman and x-ray photoemission spectroscopy

Abstract

Amorphous nitrogenated carbon (a-CN:H) films are prepared from a mixture of methane and nitrogen in an electron cyclotron resonance plasma at a pressure of 2 mTorr and applying a substrate bias of −300 V. Based on the characterization done by x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy on the films containing different amounts of nitrogen, a similarity in variation between the binding energy of C 1s peak and position of Raman active G peak is noticed. XPS C 1s and N 1s are deconvoluted into four components to separate the contribution of CC, C–N, C=N, and C≡N bonds. The change of intensity ratio of Raman active D and G peaks shows a marked correlation with the intensity ratio of single and double bonds between carbon and nitrogen. Combined XPS and Raman spectroscopy throw some light on the variation in structure of carbon films as a function of nitrogen concentration.