Search for content and authors
 

Optical and electrical properties of sputtered Zr-Si-N thin films: from solid solution to nanocomposite

Cosmin S. Sandu Farida Medjani Rosendo Sanjines 1

1. Ecole Polytechnique Federale de Lausanne (EPFL), Ecublens, Lausanne 1015, Switzerland

Abstract

DC reactive magnetron sputtering was used for the deposition of Zr-Si-N thin films. Four series of samples have been deposited at various substrate temperatures TS: room temperature, 240 °C, 440 °C and 640 °C. The total pressure was 0.6 Pa. Depending on TS, for obtaining nearly stoichiometric ZrN films, the nitrogen partial pressure was kept constant for each series at 5 %, 12.5 %, 37.5 % and 65%, respectively. Si content (CSi) was varied in each series by changing the power applied on the Si target, whereas that on Zr target was kept constant. Electrical resistivity measurements have been performed between 20 and 300 K. The resistivity measured as a function of temperature reveals variations of the temperature coefficient of resistivity as a function of Si concentration. The results of theoretical fitting using the grain boundary scattering model show that the transport properties change with Si addition from a moderated damping regime to a strong damping regime. The optical properties of the Zr-Si-N films with CSi ≤ 10 at. % can be well explain by straight forward modeling of their dielectric functions by a set of Drude-Lorentz oscillators under the assumption that the films are single, though defective, phase. In this model, the Drude dumping factor Γp (or time relaxation of the free carriers) is mainly related to the film morphology, i.e. the crystallite size and the nature of the grain boundary barrier for electrons scattering. The electron transmission probability G (obtained from fitting of resistivity measurements), the Si coverage on the ZrN grain surfaces (obtained from structural model calculation) and the Drude dumping factor Γp (obtained from fitting the real part of the dielectric function behaviour) are well correlated.

 

Legal notice
  • Legal notice:
 

Related papers

Presentation: Oral at E-MRS Fall Meeting 2006, Symposium A, by Rosendo Sanjines
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-15 10:48
Revised:   2009-06-07 00:44