Comparison between conventional and hollow cathode magnetron sputtering systems on the growing of titanium dioxide thin films: a correlation between the gas discharge and film formation

Technological Institute of Aeronautics, Department of Physics, Plasma Science and Technology Laboratory, 12228-900, São José dos Campos, SP, Brazil

^a e-mail: daduarte@ita.br

Received: 10 November 2010
Accepted: 11 February 2011
Published online: 18 May 2011

Abstract

This paper reports the deposition of titanium dioxide thin films on p-type Si(100) substrates using two techniques called conventional magnetron sputtering (CMS) and hollow cathode magnetron sputtering (HCMS). The influence of the plasma parameters on the film characteristics (topography, morphology and crystallinity) was investigated. Films were deposited at different oxygen concentrations (in the Ar + O₂ gas mixture) and axial distances for fixed values of working pressure (5.0 mTorr) and DC power (55 W). They were analyzed by profilometry, AFM and XRD. The gas discharge was diagnosed by single Langmuir probe and OES. Under experimental conditions used in this work, results show that HCMS favors the growing of rutile phase due to the increase of the energy on the film surface caused by the hollow cathode effect. On the other hand, films deposited by CMS present preferentially anatase phase due to the low energy transferred to the growing film. Further studies regarding the influence of plasma properties on the films formation were done in order to understand the plasma-surface correlation.