A study on the effect of growth kinetics and properties of diamond film obtained by addition of argon (similar to7vol%) into the methane/hydrogen mixture is carried out using a hot-filament chemical vapor deposition system. A negative bias was used as a nucleation enhancement method in addition to the argon dilution. The scanning electron microscopic images show well faceted crystallites with a predominance of angular shapes, corresponding to <100> and <110> crystalline surfaces. The surface nucleation density and growth rate with argon dilution is found to be two orders of magnitude higher than those without argon dilution. The micro-Raman spectra show a good-quality film whereas X-ray photoelectron spectra show existence of only carbon phase (Cl, peak). The effect of argon dilution on the microstructure of the diamond is discussed in the view of reported literature. (C) 2004 Elsevier B.V. All rights reserved.