Thickness of ion implanted layers as determined by elastic recoil detection analysis and spectroscopic ellipsometry

In the present work, titanium oxide layers formed by plasma immersion ion implantation are investigated by elastic recoil detection analysis (ERDA), and spectroscopic ellipsometry (SE). Good agreement for the layer thickness is obtained when additional phase information, from X-ray diffraction (XRD) and Raman spectroscopy, is included in the analysis. However, the broad diffusion tail visible in ERDA depth profiles of TiO2 layers formed by plasma immersion ion implantation (PIII) at elevated temperatures cannot be inferred from the ellipsometry data. The apparent contradiction can be resolved under the assumption of a change from semiconducting oxide to a metallic oxide near an O/Ti ratio of 1.5. As a result, SE could be used as in situ process control, but it is only of limit value as an in situ stand-alone diagnostic tool. (C) 2003 Elsevier Science B.V. All rights reserved.