Etching of CVD Diamond Films Using Different Techniques

Diamond films with a thickness ranging from 5 to 10 μm have been deposited on Si(100) substrates using hot filament CVD from a CH4-H2 mixture. These diamond films have been etched via plasmas generated from H2, O2, Ar and CF4 as well as via diffusion etching using transition metals, such as Co and Mn. It was found that CVD diamond is very resistant towards Ar and CF4 plasmas, while H2, O2 plasma are more aggressive towards diamond through chemical reaction between carbon and atomic hydrogen and oxygen. Columnar structure was formed after O2 plasma etching, while H2 plasma resulted in anisotropic diamond etching. Diamond etching via diffusion reaction with transition metals was not effective

ECR deposition of hydrogenated diamond-like amorphous carbon films using acetylene-oxygen plasmas

A series of hydrogenated amorphous carbon films have been grown from acetylene-oxygen mixtures using an Integrated Distributed Electron Cyclotron Resonance plasma reactor varying the relative precursor gases' ratio. The films were characterised by spectroscopic ellipsometry (SE), Nuclear Reaction Analysis (NRA) and visible Raman spectroscopy. It has been found that the increase of the oxygen's partial pressure (for a given acetylene pressure of 1 mT) results in a decrease of the deposition rate as well as a monotonic increase of the oxygen fraction up to 20% for a gas ratio (O-2/C2H2) = 1. Precisely, the increase of the oxygen's partial pressure is followed by a slight decrease of the optical band gap (namely the Tauc gap and the E-04 gap) and the films' density. The parameters of the Raman spectra (intensity ratio of D and G bands, the position and the FWHM of the G band) move towards values characteristic of sp(2) bonding denoting that oxygen incorporation dominates the etching of the sp(2) phase