Chemical Vapor Deposition of Cerium Oxide Using the Precursors [Ce(hfac)3(glyme)]

• Published in: Chemistry of materials 2000-03, Vol.12 (3), p.701-710
• Main Authors: Pollard, Kimberly D, Jenkins, Hilary A, Puddephatt, Richard J
• Format: Article
• Language: English
• Subjects: 30 DIRECT ENERGY CONVERSION; ADVANCED PROPULSION SYSTEMS; CATALYSIS; Catalysts: preparations and properties; CATALYTIC CONVERTERS; CERIUM OXIDES; CHEMICAL VAPOR DEPOSITION; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; General and physical chemistry; MATERIALS SCIENCE; Methods of deposition of films and coatings; film growth and epitaxy; Physics; PLATINUM; SILICON; SOLID OXIDE FUEL CELLS; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; TITANIUM NITRIDES
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm990455r

Precursors of formula [Ce(hfac)3{MeO(CH2CH2O) n Me}], 1 (n = 1), 2 (n = 2), and 3 (n = 3), and [{Ce(hfac)3}2{μ-MeO(CH2CH2O)4Me}], 4 (hfac = CF3COCHCOCF3), have been prepared and used as precursors for chemical vapor deposition (CVD) of films of cerium oxides on the substrates Si, Pt, and TiN. Thermal CVD at 450 °C with oxygen as carrier gas gave mixed Ce(III)/Ce(IV) oxides, and the main crystalline component was Ce4O7, but with fluoride impurity. The fluoride impurity was not observed if CVD was carried out using moist oxygen as carrier gas or if the as-deposited films were annealed in oxygen. Codeposition with [Y(hfac)3{MeO(CH2CH2O)2Me}] gave films of the mixed Ce(IV)Y(III) oxide Ce2Y2O7. The depositions of cerium oxides could be enhanced by use of a palladium precursor catalyst [Pd(2-methylallyl)(acetylacetonate)] and could then be carried out at 250 °C, giving films of CeO2. Under carefully controlled conditions, films of ceria-supported palladium could be prepared by this method. The films were characterized by using X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction techniques.