Nanocrystalline diamond deposition is investigated under a control of electron temperature in CH4/H-2/Ar plasma produced by inductively coupled rf discharge. A grid-biasing method is employed for the control of electron temperature T-c. When T-c in the processing region is similar to 2 eV, simple graphite has been deposited. On the other hand, nanocrystalline diamond has been prepared in case of low electron temperature (similar to 0.3-0.5 eV) plasma when CH4 Mixing ratio is very low (similar to 0.02). With increasing CH4 mixing ratio, the film property is changed from nanocrystalline diamond to diamond-like carbon. (c) 2005 Elsevier B.V. All rights reserved.