Investigation on anti-reflection property of nitrogen doped diamond-like carbon (DLC) films produced by RF magnetron sputtering

Abstract

Nitrogen doped Diamond-like carbon thin ®lms were deposited on n-Si and SiO 2 substrates by rf magnetron sputtering using pure graphite (99.999%) as the target material and mixtures of Ar, N 2 and H 2 for plasma generation. The dependence of structural and optical properties on nitrogen content was investigated using XPS, Raman spectroscopy, FT-IR spectroscopy, and Ellipsometry studies. It was found that as the nitrogen content was increased in the plasma, sp 2 bonding favored. Also it was observed that oxygen contamination increased with nitrogen content. Typical C-H stretching modes connected with diamond-like carbon could be seen in FT-IR spectra. The D and G bands were well de®ned and it was observed that as nitrogen content increased G band was enhanced. Ellipsometry studies revealed that the optical constants like refractive index (n) and extinction co-ef®cient (k) increased with increase in nitrogen content as well as substrate temperature.