BaTiO3 films of various thicknesses were grown on doped and undoped SrTiO3(100) substrates and on (La, Sr)2CuO4 films by a pulse laser deposition method. Both BaTiO3 and (La, Sr)2CuO4 films were smooth and free of particulates. X-ray diffractometry showed that all materials were three-dimensionally aligned with the cube-on-cube epitaxial relationship, and that the films obtained on SrTiO3(100) were of a c-axis-oriented tetragonal phase contrary to previous studies using metal bottom electrodes. As the film thickness decreased, the tetragonality of these films increased and the dielectric constant along the c-axis decreased rapidly, despite reduction of disorder at the interface by use of perovskite electrodes. The 2000-Å-thick BaTiO3 grown on (La, Sr)2CuO4 film had the remnant polarization of about 1.5 µ C/cm2. The results were discussed using a surface layer model.

The density and the size of particulates in films laser-deposited at room temperature using various target materials were observed to depend strongly on the target material and the laser power density. However, loose universal relations between the deposition rates and the particulate density as well as the particulate size were found, where the latter corresponds approximately to the ratio of the laser power density to the ablation threshold. Furthermore, particulates consisting of only some of the target elements such as CuOx were found. Additionally, an acceptably high deposition rate was obtained by using halide and sulfide targets. These materials offer a possibility of deposition using a low power laser.

We report long period memory retention characteristics and switching speed of (Pb, La)(Ti, Zr)O3/La2CuO4 field effect devices previously proposed by one of the authors. Most of the devices retained one-half of their initial conductance modulations induced by the ferroelectric field effect for about two weeks. Some retained memory for over 10 months, which markedly surpasses previously reported performances for the memory retention of ferroelectric field effect devices. The switching time of devices having effectively a 200-µm-long and 40-µm-wide gate area reduced to 10 µs, as the conductance between the source and drain increased. Such a short switching time is favorable for interpretation of the conductance modulation based on the field effect. Approaches to high density integration are discussed.

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Three-dimensionally aligned epitaxial (Pb,La)(Zr,Ti)O3/(La,Sr)2CuO4 multilayers were grown on SrTiO3 (100) single crystals by pulse laser deposition. A cube-on-cube epitaxial relationship of these multilayers was confirmed by the θ-2θ diffraction profile and the pole figure. The stability of their interfaces was confirmed by depth profiles and x-ray diffractometry of the as-deposited and the annealed multilayers having 100–300-Å-thick (La,Sr)2CuO4 layers. The results suggest that the multilayers can be applied to the ferroelectric field-effect transistor.