Determination of Ir consumption during thermal oxidation and PbZrxTi1-xO3 processing using Bragg-peak fringe analysis

Thickness interference fringes can be seen around the Bragg peaks of a vari ety of polycrystalline thin (10-20 nm) films using standard x-ray diffracti on techniques in a conventional Bragg-Brentano geometry. In this article, t hickness fringe analysis is used to investigate oxidation and roughening in thin Ir films with and without overlayers of the ferroelectric PbZrxTi1-xO 3 (PZT). Changes in fringe spacing were used to determine the Ir thickness consumed by oxidation. Fringe contrast degradation (indicating roughening) was observed both after oxidation anneals (which formed a surface layer of IrO2) and after subsequent reduction anneals (which converted the IrO2 back to Ir). Film overlayers were found to have a protective effect against oxi dation and roughening, as evidenced by comparison of postoxidation fringe p atterns for bare and PZT-coated Ir films. Overall, our results demonstrate that thickness fringe analysis can be used as a simple, quantitative probe of processing-induced thin film thickness and morphology changes. (C) 2001 American Institute of Physics.