A systematic study on structural and dielectric properties of lead zirconate titanate/(Pb,La)(Zr(1−x)Ti(x))O3 thin films deposited by metallo-organic decomposition technology

Abstract

Articles you may be interested inAn investigation on the leakage current and time dependent dielectric breakdown of ferroelectric lead-zirconate-titanate thin film capacitors for memory device applications Pin-hole free ferroelectric ͑Pb,La͒͑Zr 1Ϫx Ti x ͒O 3 thin films with uniform composition have been fabricated using the metallo-organic precursor compounds, which were carefully home synthesized. The structural development, spectroscopic, and dielectric properties of these films have been systematically investigated using atomic force microscopy ͑AFM͒, x-ray diffraction, Fourier transform infrared spectroscopy, Raman scattering, and dielectric measurements. It has been found from our experimental results of PZT 40/60 thin films that the overlapping of (h00) and ͑00l͒ peaks of these films in x-ray diffraction patterns, mainly due to the small grain sizes in films, makes it very difficult to distinguish individual diffraction peaks and to identify the phases. However, Raman measurements undoubtedly reveal the Raman spectra of these films in the tetragonal phase field, demonstrating that Raman spectroscopy is an effective tool to identify structures, especially in the case of thin films having very small grains. AFM results show that the PZT perovskite structure in films may grow radially by rosettes and that microcracks appear in the three-dimensional AFM pictures at grain boundaries, which may be the cause for easy dielectric breakdown. A striking feature of the AFM observation is that three polycrystalline perovskite regions intersect symmetrically at a point with 120°to each other, and a rosette growth model for the perovskite structure in PZT films is thus proposed to explain this new phenomenon. The excellent ferroelectric properties of these films, such as the high fatigue resistance and low leakage current, are attributed to the high quality of the metallo-organic solutions and to reduce the amount of oxygen vacancies in the films by optimizing the annealing conditions and by doping a suitable amount of La ions to minimize the charge blocking of oxygen vacancy at the interface by Pt electrode. It seems that the rhombohedral PZT films with softer hysteresis loops are suitable for nonvolatile random access memory application.

High oxygen-pressure annealing effects on the ferroelectric and structural properties of PbZr0.3Ti0.7O3 thin films

“…These peaks are well known and have been identified as E͑2TO͒, B I + E, A I ͑2TO͒, and A I ͑3TO͒, respectively. 22 The results of this figure also show that increasing P O 2 results in appreciable changes in the spectral lines. These changes mainly occur in the relative intensity of all modes.…”

“…The Zr/ TiO 6 metal-oxygen octahedral vibrational modes obtained through these measurements indicated changes in the crystal structure of the PZT perovskite phase due to increasing O 2 pressure. 22 Figure 2 displays the FT-IR spectra of the PZT/ Pt͑111͒ / Ti/ SiO 2 /Si͑100͒ films, whose backgrounds were corrected by a careful subtraction of the background arising from the substrate. The spectrum belonging to the film annealed in air ( Fig.…”

Depósito mediante ablación con láser de láminas delgadas de (Pb,La) TiO₃ y ZnO sobre (100) InP

“…Su superficie se muestra granular (figura 3b), con l-bulos submicromŽtricos de simetr'a radial caracter'sticos de la fase perovskita (22,23). La rugosidad superficial media del PLT es de 4 nm, lo que corresponde al 1.5% del espesor de la l ‡mina.…”

Dependence of crystalline, ferroelectric and fracture toughness on annealing in Pb(Zr0.52Ti0.48)O3 thin films deposited by metal organic decomposition

“…Many methods such as pulsed laser ablation (PLD), rf sputtering, chemical vapor deposition (CVD), metal organic decomposition (MOD), sol-gel process and multiple electrophoretic deposition are used to prepare ferroelectric thin films [2][3][4][5][6][7] . MOD is one of the considerable deposition methods, since it is a non-gelling chemical process in which molecular homogeneity is attained in the liquid phase, and the solutions can be produced without solution gelling and at a lower processing temperature 5 .…”

“…Many methods such as pulsed laser ablation (PLD), rf sputtering, chemical vapor deposition (CVD), metal organic decomposition (MOD), sol-gel process and multiple electrophoretic deposition are used to prepare ferroelectric thin films [2][3][4][5][6][7] . MOD is one of the considerable deposition methods, since it is a non-gelling chemical process in which molecular homogeneity is attained in the liquid phase, and the solutions can be produced without solution gelling and at a lower processing temperature 5 . Few reports have shown that the microstructural charactheristics and electrical properties of PZT thin films depend greatly on the annealing temperature 8 and film thickness [9][10][11] , however little has been done in regard to the dependence of ferroelectric properties and fracture toughness on annealing procedure.…”