Magnetron sputtered NbN thin films and mechanical properties

• Published in: Surface & coatings technology 2004-02, Vol.179 (2), p.188-192
• Main Authors: Han, Zenghu, Hu, Xiaoping, Tian, Jiawan, Li, Geyang, Mingyuan, Gu
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Magnetron sputtering; Materials science; Mechanical and acoustical properties; Mechanical properties; Methods of deposition of films and coatings; film growth and epitaxy; Microstructure; NbN thin films; Physical properties of thin films, nonelectronic; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(03)00848-X

In this study, NbN thin films were deposited by reactive magnetron sputtering at different N 2 partial pressures and at room temperature. X-Ray diffraction analysis, transmission electron microscopy and atomic force microscopy were employed to characterize their phases, microstructure and surface morphology. Their microhardness and elastic modulus were evaluated using a microhardness tester and the effects of N 2 partial pressure on the phase formation, microstructure and mechanical properties of NbN thin films were investigated. The results show that there are clear effects of N 2 partial pressure on the deposition rate, phases, hardness and elastic modulus of magnetron sputtered NbN films. At a low N 2 partial pressure, the deposition rate is higher, while hcp β-Nb 2N and fcc δ-NbN coexist in NbN films. With the increase of N 2 pressure, the deposition rate decreases and the films are single-phase fcc δNbN; accordingly, the hardness and modulus reach peak values of 36.6 GPa and 457 GPa, respectively. A further increase of the N 2 partial pressure will cause hcp ε-NbN to appear in NbN films and then the hardness and modulus of films decrease.