The effect of nitrogen incorporation in DLC films deposited by ECR Microwave Plasma CVD

• Published in: Applied surface science 2014-09, Vol.314, p.46-51
• Main Authors: Seker, Z., Ozdamar, H., Esen, M., Esen, R., Kavak, H.
• Format: Article
• Language: English
• Subjects: 61.05.Tv; 68.55.J; 68.60.Bs; 78.55.Qr; 81.05.U; Carbon; Chemical vapor deposition; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Diamond like carbon; Diamond-like carbon films; DLC; Doping; ECR Microwave Plasma CVD; Exact sciences and technology; FTIR; Physics; Resistivity; Silicon substrates; XPS
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.06.137

•DLC and DLC:N thin films have been fabricated by the Electron Cyclotron Resonance Microwave Plasma Chemical Vapor Deposition (ECR- MP CVD) System at room temperature.•DLC:N thin films were obtained by nitrogen doping.•Surface of the films was very smooth.•XPS, RAMAN and FT-IR measurements confirmed the formation of sp2 CN and sp3 CN bonds.•DLC and DLC:N films were found to be very hard.•All the films showed high optical transparency in the IR region. Diamond like carbon (DLC) and nitrogenated diamond like carbon (DLC:N) films have been deposited by electron cyclotron resonance microwave plasma chemical vapor deposition (ECR-MP CVD) on Si (110), steel and glass substrates, using CH4 and N2 as plasma source. The effect of nitrogen doping on the optical, electrical, structural and mechanical properties of films was investigated. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy results showed that sp2 bonded carbon phases increased while the sp3 bonded carbon phases decreased by nitrogen doping. Microhardness measurements showed a decrease in hardness (from 75 to 69GPa) according to nitrogen incorporation. Average transmittance of all the films was over 90% and band gap energy (Eg) of the films decreased due to increasing nitrogen flow rate. The film morphology was studied using the atomic force microscopy (AFM). Electrical properties were characterized by Hall measurement. Undoped DLC was p-type with a conductivity of 9.81×10−6 (Ωcm)−1. DLC films became n-type by nitrogen doping. The best conductivity value for the nitrogen doped DLC films was found 2.77×10−5 (Ωcm)−1. PL spectra of DLC and DLC:N films showed three peaks at 405nm (3.06eV), 533nm (2.32eV) and 671nm (1.84eV).