Structural and chemical properties of sputter-deposited Ti–Ge–N thin films

• Published in: Surface & coatings technology Vol. 200; no. 5; pp. 1483 - 1488
• Main Authors: Sandu, C.S., Sanjinés, R., Benkahoul, M., Parlinska-Wojtan, M., Lévy, F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 21.11.2005; Elsevier
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Multilayer; Other topics in materials science; Physics; Production techniques; Sputtering; Structural properties; Surface treatment; Titanium nitride; Titanium nitride; Multilayer; Structural properties; Sputtering; Nitrides; Multiple layer; Chemical properties; Microstructure; Coatings; Surface treatment; Thin film
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2005.08.056

Ti–Ge–N single-layer and TiN/GeN-multilayer thin films were deposited by reactive magnetron sputtering on Si and WC–Co substrates at constant temperature T s = 240 °C, from confocal Ti and Ge targets in a mixed Ar/N 2 atmosphere. The nitrogen partial pressure, the TiN deposition time t Ti and the power on the Ti and Ge targets were kept constant. In order to obtain various GeN layer thicknesses in the films, the deposition time ratio t Ge/ t Ti was varied. TiN/GeN multilayer films with TiN thickness ∼ 5 nm and various GeN thicknesses between 0.5 and 5 nm were deposited. A nanocrystalline multilayer film is formed, where the suppression of crystal growth is controlled by the successive deposition of two phases. TEM investigations revealed important changes induced by GeN x thickness variation: the columnar single-layer morphology switches into a multilayer morphology. The critical GeN thickness for changing the type of morphology is controlled by the diffusion of Ge atoms at the TiN crystallite boundaries. The morphology modification from single-layer to multilayer type determines the film hardening. Electron probe microanalyses (EPMA), scanning tunneling microscopy (STM), transmission electron microscopy (TEM), nanoindentation and X-ray diffraction (XRD) techniques were employed to characterize single- and multilayer films. The properties of alternate-deposited films are compared to those of co-deposited ones and interpreted.