Innovative second-generation Ba and Sr precursors for chemical vapor deposition of Ba1-xSrxTiO3 thin films

Ba1-xSrxTiO3 (BST) thin films, appealing candidates for innovative applications in microelectronics, have been obtained by chemical vapor deposition using innovative second-generation Ba and Sr molecular precursors, namely, [Ba(thd)(2)(pmdien)(Meim)] (thdH = 2,2,6,6 - tetramethyl-3,5-heptanedione; pmdien = N, N, N', N", N"-pentamethyldiethylenetriamine- Meim = methylimidazole) and [Sr-2(thd)(4)(imH)(2)(EtOH)](imH = imidazole). Titanium tetraisopropoxide Ti((OPr)-Pr-i)(4) was used as the Ti source. Film preparation was carried out on quartz and Si(100) substrates at 450 degrees C under a nitrogen + oxygen atmosphere followed by annealing in air at temperatures up to 800 degrees C. The structural, compositional, and morphological evolution of the films was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy, with particular focus on the interplay between the system properties and the processing conditions. The formation of nanophasic BST layers (crystallite size < 30 nm) required a minimum annealing temperature of 800 degrees C. (c) 2006 The Electrochemical Society.