Composition, structure, and ac conductivity of rf-sputtered calcia-stabilized zirconia thin films

Abstract
Thin 12 mole% calcia‐stabilized zirconia CSZ films (500–17 000 Å) were deposited by rf sputtering onto single‐crystal silicon substrates. When deposited in an oxygen‐containing plasma (more than 0.2% O2 in Kr), such films appeared to be stoichiometric, as verified by nuclear microanalysis; while their structure, analyzed by x rays, appeared to be of the fluorite type. The ac conductivity measured on Al/CSZ/Si structures between 200 and 400 °C suggests an activation energy and a preexponential factor close to that of bulk‐sintered material having the same composition. This result tends to prove that conductivity in sputtered CSZ thin films is due to anion‐oxygen movement. Preliminary emf measurements on Pt/O2/CSZ/Ni/Si thin‐film galvanic cells confirmed this interpretation.