The charge-trapping memory devices with a structure Pt/Al2O3/(Ta2O5)x(TiO2)1−x/Al2O3/p-Si (x = 0.9, 0.75, 0.5, 0.25) were fabricated by using rf-sputtering and atomic layer deposition techniques. A special band alignment between (Ta2O5)x(TiO2)1−x and Si substrate was designed to enhance the memory performance by controlling the composition and dielectric constant of the charge-trapping layer and reducing the difference of the potentials at the bottom of the conduction band between (Ta2O5)x(TiO2)1−x and Si substrate. The memory device with a composite charge storage layer (Ta2O5)0.5(TiO2)0.5 shows a density of trapped charges 3.84 × 1013/cm2 at ± 12 V, a programming/erasing speed of 1 µs at ± 10 V, a 8% degradation of the memory window at ± 10 V after 104 programming/erasing cycles and a 32% losing of trapped charges after ten years. The difference among the activation energies of the trapped electrons in (Ta2O5)x(TiO2)1−x CTM devices indicates that the retention characteristics are dominated by the difference of energy level for the trap sites in each TTO CTM device.

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Uniformly patterned Pt∕PbTiO3∕PbZr0.3Ti0.7O3∕PbTiO3∕Pt capacitor arrays were etched in noncrystalline phase. The ferroelectric layer was well crystallized and contains uniform grains. The capacitors exhibit well-saturated hysteresis loop and excellent fatigue properties in terms of larger saturation polarization Pmax of 53.2μC∕cm2 at an applied voltage of 12V, higher remnant polarization Pr of 30.5μC∕cm2 for a coercive field of 58kV∕cm, remnant polarization of about 81.2% at 1010 switching cycles, and a low leakage current density of 10−8A∕cm2 at an applied voltage of 3V. The etching effects on the properties of capacitor were reduced to minimal values, confirmed by scanning electron microscope, energy-dispersive x-ray microanalysis, and piezoresponse force microscopy results. The reliable electric properties and fine profile of the patterns indicate that the capacitors are suitable for ferroelectric random access memories and other integrated ferroelectric devices.