Carbide formation in tungsten-containing amorphous carbon films by annealing

Tungsten-containing amorphous carbon films were produced by dual magnetron sputter deposition. The formation of carbide phases after heat treatment in inert gas at temperatures up to 2800 K was investigated by X-ray diffraction for tungsten concentrations below 25 at%. After deposition, each film consists of an amorphous carbon matrix with atomically dispersed W inclusions. Annealing up to 2800 K leads to a formation of carbide phases and to nano clustering. Three tungsten carbide phases were observed (WC, W2C, WC1−x), mostly as mixtures of two phases. The phase combination depends on annealing temperature and W concentration. Additionally, nano diffraction was performed in a scanning transmission electron microscope, to determine the phase of single crystallites at scales, where X-ray diffraction fails. keywords: Plasma-Materials Interaction, Carbon-based amorphous films, Chemical Reactions *Corresponding author e-mail: [email protected] *Corresponding author address: Boltzmannstrasse 2, 85748 Garching, Germany *Corresponding author phone: + 49 89 3299 1923 *Corresponding author fax: + 49 89 3299 1212