EFFECT OF ION-IMPLANTATION DOPING ON ELECTRICAL-PROPERTIES OF YTTRIA-STABILIZED ZIRCONIA THIN-FILMS

The change in conductivity of Fe and Ti implanted rf-sputtered layers of yttria-stabilized zirconia (YSZ) was studied as a function of the temperature (400-800-degrees-C) and oxygen partial pressure. In an oxidized state and in the temperature range of 400-600-degrees-C, the conductivity of the Fe implanted YSZ film (15 keV, 8 x 10(16) at.cm-2) was dominated by the n-type electronic conductivity of a thin Fe2O3 layer with an estimated thickness of less than 2 nm on top of the YSZ thin film. Due to the incorporation of a part of the implanted Fe atoms in the yttria-stabilized zirconia lattice, the ionic conductivity was somewhat decreased. In a reducing atmosphere this electronic conduction was no longer observed. In an oxidized state, the conductivity of the YSZ film was not influenced by the implantation of Ti (15 keV, 8 x 10(16) at.cm-2). After reduction in a H2 atmosphere, an increase in the conductivity of the sputtered film with 2-3 orders of magnitude was observed. This has been ascribed to the presence of nonstoichiometric TiO2-x, which is an n-type semiconductor.