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Since the discovery of ferroelectricity in doped HfO2 and ZrO2 thin films over a decade ago, fluorite‐structured ferroelectric thin films have attracted much research attention due to their excellent scalability and complementary metal‐oxide semiconductor compatibility compared to conventional perovskite ferroelectric materials. Although various factors influencing the formation of the ferroelectric properties are identified, a clear understanding of the causes of the phase formation have been difficult to determine. In this work, ZrO2 films deposited by atomic layer deposition and chemical solution deposition have resulted in films with completely different structural properties. Regardless of these differences, a general relationship between strain and phase formation is established, leading to a more unified understanding of ferroelectric phase formation in undoped ZrO2 films, which can be applied to other fluorite‐structured films. [ABSTRACT FROM AUTHOR]

Inducing and detecting the polar orthorhombic phase are crucial for the establishment of ferroelectricity in HfO2‐ and ZrO2‐based thin films. Unfortunately, commonly used structural characterization techniques such as grazing incidence angle X‐ray diffraction (GIXRD) only partially allow an accurate detection of this crystalline phase, whose characteristic pattern almost coincides with the one of the tetragonal phase. As a consequence, phase determination is commonly based on peak deconvolution tracing the position of the main peak at 2θ values of around 30°, which can be assigned both to the t(101) and the o(111) plane directions and additionally be influenced by mechanical stress in the layers. Alternatively, epitaxial layers are required to differentiate the phase. Herein, using an integrated experimental–computational approach, it is shown how Raman spectroscopy can distinguish between the monoclinic, the tetragonal, and the orthorhombic phase of ZrO2. The Raman spectra calculated from first principles match the experimentally measured data and thus enable an unambiguous phase assignment. Therefore, Raman spectroscopy proves to be a powerful technique for discerning the three main crystalline phases in these materials. As demonstrated by the good agreement between structural and electrical data, it can therefore be used to predict ferroelectricity in the addressed layers. [ABSTRACT FROM AUTHOR]

The effects of thermal annealing on Pb(Zr0.3Ti0.7)O3 ferroelectric thin film capacitors derived by chemical solution deposition with Pt electrodes were investigated. Sample-averaged structural information of the capacitors with different thermal histories was obtained from fitting the X-ray specular reflectivity using a homogeneous stratified multilayered structure model of Pt/PZT/Pt/TiOx/SiO2. Electrical measurements showed a remarkable remanent polarization reduction of up to 8.8% and an increase of the dielectric constant at low biases with increasing annealing time from 5 to 10 min. However, no evident change to the fatigue endurance was found except for the reduced initial remanent polarization. The effects of the thermal annealing on the electrical propel-ties of the ferroelectric capacitors are discussed in correlation with the structural changes in the ferroelectric thin films. [ABSTRACT FROM AUTHOR]

Abstract: An excimer laser (KrF, 248nm) was used to crystallize barium strontium titanate thin films of thickness 95nm. Numerical simulation was first performed to get an idea about the laser energy suitable for crystallization. Amorphous films deposited by chemical solution deposition were irradiated at different energies with different frequencies (40–l50Hz), laser fluences (100–150mJ/cm2) and pulses (400–1000) while maintaining the substrate at 25 and 250°C. Films were found to crystallize above 100mJ/cm2 in both cases. Films crystallized with substrate temperatures of 250°C were noticed to have less cracks. The microstructure of these films were analyzed with a scanning electron microscope. From the XPS analysis, it is inferred that the top few nanometers have a different structure compared to normal furnace annealed thin films. This top surface layer was found to be dependent on the laser energy used for crystallization. The dielectric constant was found to increase from 60 to 180 for the 95nm thin films on increasing the laser fluence. Films crystallized with 120mJ/cm2 while maintaining a substrate temperature of 250°C have leakage current densities of 1×10 −7 A/cm2 at 1.5V and a dielectric constant of 200. [Copyright &y& Elsevier]

Since the discovery of ferroelectricity in doped HfO2 and ZrO2 thin films over a decade ago, fluorite‐structured ferroelectric thin films have attracted much research attention due to their excellent scalability and complementary metal‐oxide semiconductor compatibility compared to conventional perovskite ferroelectric materials. Although various factors influencing the formation of the ferroelectric properties are identified, a clear understanding of the causes of the phase formation have been difficult to determine. In this work, ZrO2 films deposited by atomic layer deposition and chemical solution deposition have resulted in films with completely different structural properties. Regardless of these differences, a general relationship between strain and phase formation is established, leading to a more unified understanding of ferroelectric phase formation in undoped ZrO2 films, which can be applied to other fluorite‐structured films. [ABSTRACT FROM AUTHOR]