Novel fatigue-free layered structure ferroelectric thin films

For the first time, fatigue-free ferroelectric thin-film capacitors have been fabricated, using pulsed laser deposition, with the layer-structure family of oxides as the ferroelectric material. Stoichiometric thin films of layer-structured SiBr2(TaxNb2−x)O9 (0 < x < 2) compounds were successfully deposited on platinized Si/SiO2 wafers. Technological opportunities now exist for the development of commercially viable ferroelectric random access memory devices using these materials. So far, this has been primarily hindered by degradation problems such as fatigue in the currently investigated ferroelectric thin film capacitors, e.g. PbZrxTi1−xO3 films on Pt electrodes. The identification of these fatigue-free thin-film materials and their processing, structure and properties are discussed in this paper. The films show very good hysteresis characteristics with a remnant polarization value of 11 μC cm−2, and no fatigue was observed up to 109 switching cycles.