Hydrogen analysis in diamond-like carbon by glow discharge optical emission spectroscopy

Glow discharge-optical emission spectroscopy (GD-OES) was evaluated for hydrogen analysis in diamondlike carbon (DLC) films. DLC film samples were prepared using the plasma-based ion-implantation and deposition method (PBIID). Their hydrogen contents were determined using elastic recoil detection analysis (ERDA). The hydrogen intensity obtained by GD-OES increased gradually concomitantly with increasing hydrogen contents at the lower hydrogen content region. However, the intensity increased drastically at the higher hydrogen content region of more than about 30 at%. When the hydrogen contents increased, the correlation between GD-OES hydrogen intensity and ERDA hydrogen contents was deviated from the linear relation obtained for hydrogen-implanted silicon samples as reference materials. The sputtering rate of the DLC sample was found to vary at the high H content region. A linear relationship was obtained between the hydrogen contents and GD-OES intensities corrected with the sputtering rate of samples.