Preparation of ZrO2-MgO Thin Films by OMCVD

Thin films of ZrO2, MgO and magnesia stabilized zirconia (MSZ) were prepared in a reduced pressure (5-20 Torr) on glass and alumina substrates by organometallic chemical vapor deposition (OMCVD) using zirconium alkoxide, Zr(O-tBu)4, and magnesium acetylacetonate, Mg(C5H7O2)2, as the starting organometallic compounds. ZrO2 films of various phases (amorphous, tetragonal and monoclinic phases) were formed at the deposition temperatures from 200° to 600°C by pyrolysis of Zr(O-tBu)4. Amorphous MgO films were grown at the deposition temperatures from 450° to 700°C by pyrolysis of Mg(C5H7O2)2 which was transported with oxygen carrier gas. Heat treatment of the as-grown films was required in order to eliminate the residual free carbon. Fully or partially stabilized zirconia films were obtained at 10 Torr by a simultaneous pyrolysis of Zr(O-tBu)4 and Mg(C5H7O2)2 in the deposition temperatures from 450° to 700°C, where the MgO concentration (0-18.5mol%) in MSZ was controlled by the respective carrier gas flow rates at a given saturation temperature of each complex. The electrical conductivity of fully stabilized films (cubic phase) which were prepared above 700°C on an alumina substrate, increased slightly with MgO concentration in MSZ and showed an activation energy for conduction of about 1.2eV.