Chemical vapor deposition of cerium oxide using the precursors [Ce(hfac)(3)(glyme)]

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){mu-MeO(CH2CH2O)(4)Me}], 4 (hfac = C F3COCHCOCF3), have been prepared and used as precursors for chemical vapor deposition (CVD) of films of cerium oxides on the substrates Si, Pt, and Ti N. Thermal CVD at 450 degrees C with oxygen as carrier gas gave mixed Ce(II I)/Ce(IV) oxides, and the main crystalline component was Ce4O7, but with fl uoride 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 ann ealed in oxygen. Codeposition with [Y(hfac)(3){MeO(CH2CH2O)(2)Me}] gave fil ms of the mixed Ce(IV)Y(III) oxide Ce2Y2O7. The depositions of cerium oxide s could be enhanced by use of a palladium precursor catalyst [Pd(2-methylal lyl)(acetylacetonate)] and could then be carried out at 250 degrees C, givi ng films of CeO2. Under carefully controlled conditions, films of cer ia-su pported palladium could be prepared by this method. The films were characte rized by using X-ray photoelectron spectroscopy, scanning electron microsco py, and X-ray diffraction techniques.