Anode-supported planar solid oxide fuel cells by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) and electrostatic spray deposition(ESD): Fabrication of dense thin layers of yttria-stabilized zirconia by PE-MOCVD

This paper reports a study of plasma-enhanced metalorganic chemical vapor d eposition (PE-MOCVD) as a suitable technique for depositing dense, crack-fr ee thin layers of yttria-stabilized zirconia onto porous substrates, as a s tep in the fabrication of anode-supported planar solid oxide fuel cells (SO FC). Our objective is to present an alternative method by which an SOFC ass embly may be fabricated at lower temperature than by conventional methods. PE-MOCVD using zirconium tert-butoxide (ZrTB) and yttrium hexafluoroacetyla cetonate dihydrate (Y6FA) is capable of producing the electrolyte in thin d ense layers on smooth surfaces, as demonstrated for Si(110) wafers. If a po rous substrate is used, the average surface pore size should not exceed 1-2 mum to obtain a dense film. The crystalline phase of the film was related to the Y6FA concentration in the gas phase using x-ray diffraction. Depth p rofiling, using x-ray photoelectron spectroscopy, showed that Y is present (fairly uniform) at all depths of the film. Growth rates are dependent on t he applied power but independent of substrate temperature. Film density, ho wever, shows a significant dependence on substrate temperature.