Nanocrystalline diamond deposition in electron-temperature-controlled CH4/H2/Ar plasma

Nanocrystalline diamond deposition is investigated under a control of electron temperature in CH4/H2/Ar plasma produced by inductively coupled rf discharge. A grid-biasing method is employed for the control of electron temperature Te. When Te in the processing region is ∼ 2 eV, simple graphite has been deposited. On the other hand, nanocrystalline diamond has been prepared in case of low electron temperature (∼ 0.3–0.5 eV) plasma when CH4 mixing ratio is very low (∼ 0.02). With increasing CH4 mixing ratio, the film property is changed from nanocrystalline diamond to diamond-like carbon.