Structure and Optical Characteristics of DLC Films: A Study on the Impact of CH4 Flow Rate

Using a RF‐Plasma Enhanced Chemical Vapor (RF‐PECVD) Depositions method, employing hydrogen and methane gas, Diamond like carbon (DLC) films were fabricated on glass and silicon substrates. The impact of varying CH4 to H2 ratios on the resulting film's structure, optical characteristics, and mechanical properties was investigated. The deposition process occurred at methane flow rates spanning 5 to 40 sccm. The films' surface morphology, and roughness were analyzed through Atomic Force Microscopy. Moreover, the Vickers hardness tests was employed to determine the hardness of produced films. The optical behavior of the DLC thin films was explored utilizing UV‐visible spectrometry and ellipsometry. A thorough investigation was conducted to understand how the CH4 flow rate influences layer growth, morphology, topography, and how these factors relate to the films' transmittance, reflectance, refractive index, and optical band gap.