Abstract
In this paper, we discuss on the versatility of nanocrystalline diamond (NCD) film properties as a function of the process parameters aiming to properly fulfil the requirements for various applications. NCD films are achieved in Ar/H~2~/CH~4~ microwave discharges. Their characteristics are changed by varying the depo‐sition parameters: pulsed and continuous discharges, hydrogen concentration, microwave power, surface temperature, and N~2~ ratio in the gas mixture as impurity. SEM, Raman spectroscopy, X‐ray diffraction, AFM and electrical measurements (Arrhenius diagrams) are performed in order to assess the film properties. The microstructure and phase purity, that mainly determine the surface roughness, electrical resisti‐vity, and growth rate, critical parameters for industrial applications such as mechanics and electronics, are particularly examined. The results point out the flexibility of the microwave plasma assisted process, suitable to straightforwardly control and adapt NCD film properties to the expected applications. Thus, a transition from nanocrystalline to microcrystalline structures is easily obtained with different amounts of non‐diamond phases, leading to surface roughness increasing from 20 nm to 80 nm and keeping appreciable growth rates around 1 µm h^–1^. The most striking results concern the wide range of the film transversal resistance values measured at room temperature, evolving from 400 Ω for graphite‐like NCD film to 3 × 10^12^ Ω for microcrystalline diamond. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)