Optical properties of amorphous carbon nitride synthesized on Si by ECR-CVD

Amorphous carbon nitride films have been synthesized on silicon using an electron cyclotron resonance chemical vapor deposition (ECR-CVD) system combined with a negative dc bias and a mixture of C2H2, N2 and Ar as precursors. The refractive index and extinction coefficient of the amorphous carbon nitride films are characterized by N&K analyzer. The optical band gap energy derived by Taucʹs equation decays with increasing substrate negative dc bias, ECR-power, flow rate ratio of N2/C2H2, nitrogen to carbon ratio (N/C) determined by X-ray photoelectron spectroscopy (XPS) and with the increase of graphitic content was examined by Raman spectroscopy.