AVS 66th International Symposium & Exhibition
    Thin Films Division Friday Sessions
       Session TF-FrM

Paper TF-FrM11
The Use of Molecular Oxygen for a Low Cost and Low Temperature ALD of Amorphous Titania

Friday, October 25, 2019, 11:40 am, Room A216

Session: Theory and Characterization of Thin Film Properties
Presenter: Harshdeep S. Bhatia, University of Illinois at Chicago
Authors: H.S. Bhatia, University of Illinois at Chicago
C.G. Takoudis, University of Illinois at Chicago
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The interest in Titania films has been increasing in the past few decades. This interest can be attributed to the various applications of ultrathin films of Titanium dioxide. The thin film deposition of amorphous titania can be done at a low temperature using tetrakis(dimethylamido) titanium (TDMAT) along with ozone and oxygen; growth rates have only been reported at temperatures greater than 150 °C. For titania use with organic substrates‚ it is important that the reaction is performed at low temperatures to prevent denaturation and degradation. The use of Ozone has also been reported to cause degradation in some elastomeric polymers. Along with the high cost of manufacturing a high concentration of ozone‚ Oxygen could be considered as a replacement for Ozone. In this study‚ growth temperatures at or below 150 °C were used to uniformly deposit amorphous titania using TDMAT and oxygen using a highly sophisticated pulse gas source (c/o Kurt J Lesker Co.) ensuring a constant pressure of gas is pulsed into the reactor which is believed to be the contributing factor in the success of this reaction. The as-deposited films were characterized using Spectroscopic Ellipsometry (SE) and X-ray Photoelectron Spectroscopy (XPS). Applications of this reaction could lead to low temperature deposition of titanium oxide on organic substrates for the use in biomedical implants, as a protective coating‚ and as a seed layer to deposit other conductive metals on organic substrates. One of the interesting phenomena observed using SE was the appearance of a very small but non-zero extinction coefficient in the visible range. This extinction coefficient was similar to the urbach tail absorption usually observed in the UV range. This could also point towards slight absorption of visible light by the deposited Titania films which opens new avenues for research in photocatalytic activity of Titania films within the visible light spectrum.