Atmospheric pressure MOCVD of TiO2 thin films using various reactive gas mixtures

TiO2 thin films were deposited under atmospheric pressure by chemical vapor deposition using metal organic precursors (AP-MOCVD) in the temperature range 350-700 degreesC on Si(100) and stainless steel substrates. Titanium tetraisopropoxide (TTIP) was used as metal source. The influence on the growth process of an oxidant co-reagent (O-2 and H2O) has been investigated. TTIP mole fraction and the substrate temperature are the major parameters which permit a good control of the morphology, the microstructure, the composition and the growth rate of these functional oxide thin films. Addition O-2 in the input gas phase does not change significantly the main features of the layers. By contrast, TTIP/ H2O gas mixtures exhibit a higher reactivity leading to the deposition of TiO2 at lower temperature and with a higher growth rate. For instance, the deposition rate at 450 degreesC is approximately 440 and 90 nm/min with and without H2O vapor, respectively. Single-phased (anatase or Futile) and bi-phased coatings with a controlled composition can be deposited depending on the temperature and the TTIP mole fraction. (C) 2004 Elsevier B.V. All rights reserved.