TEM characterisation of PZT films prepared by a diol route on platinised silicon substrates

Kaewchinda, Darunee; Chairaungsri, T.; Naksata, Manoch; Milne, Steven J.; Brydson, Rik

doi:10.1016/s0955-2219(99)00296-4

Cited by 48 publications

(38 citation statements)

References 20 publications

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“…Enthalpies of solution of Pb in Pt, Cu and Ag have been calculated as -16, +23 and +9 kJ/mol, respectively [33]. Intermetallic Pt-Pb phases like Pt 5−7 Pb [34,35] and Pt 3−4 Pb [36] are also believed to serve as nucleation seeds for PZT(111) orientation during growth of PZT on Pt. As an additional term the surface energy of the deposited materials might be lowered by segregation of the substrate species to its surface (surfactant effect).…”

Section: Resultsmentioning

confidence: 99%

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes

Chen¹,

Schafranek²,

Wu³

et al. 2011

J. Phys. D: Appl. Phys.

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Abstract.The interface formation between Pb(Zr,Ti)O 3 and Pt, Cu and Ag was studied using in situ photoelectron spectroscopy. A strong interface reaction and a reduction of the substrate surface is observed for all three interfaces as evidenced by the appearance of metallic Pb species. Despite the different work function of the metals, nearly identical barrier heights are found with E F − E VB = 1.6 ± 0.1 eV, 1.8 ± 0.1 eV and 1.7 ± 0.1 eV of the as-prepared interfaces with Pt, Cu and Ag, respectively. The barrier heights are characterized by a strong Fermi level pinning, which is attributed to an oxygen deficient interface induced by the chemical reduction of Pb(Zr,Ti)O 3 during metal deposition.

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Section: Resultsmentioning

confidence: 99%

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes

Chen¹,

Schafranek²,

Wu³

et al. 2011

J. Phys. D: Appl. Phys.

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“…However, for the fabrication films <100 nm, the amount of excess Pb required to produce single-phase materials is so large that it leads to other issues which decrease both dielectric constant (K) and resistivity. [1,25,26] Under the reducing conditions present during pyrolysis, Pb from the film can react with, and diffuse into, the Pt electrode, as evidenced both by diffusion studies and the observation of transient intermetallic phases. [27][28][29][30] Further, Ti distribution within PZT-based layers can be highly nonuniform due to both interactions with the bottom electrode and preferential nucleation of Ti-rich perovskite phases.…”

mentioning

confidence: 99%

Reversibility of the Perovskite‐to‐Fluorite Phase Transformation in Lead‐Based Thin and Ultrathin Films

et al. 2008

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Lead-based perovskite materials currently form the basis of an approximately $5 billion/year market because of their outstanding ferroelectric and electromechanical properties. The volatility of the Pb cation at the elevated temperatures required for material fabrication and phase development has always created difficulties, because even slight deviations from the proper stoichiometry lead to the formation of a non-ferroelectric (and property-destroying) fluorite phase. As researchers strive to integrate these materials into nanometer-scale devices, they are finding that the traditional methods of Pb stoichiometry control are no longer effective owing to increased surface/volume ratio and enhanced interactions with commonly used Pt electrodes.[1] We demonstrate a novel approach for the fabrication of lead zirconate titanate (PZT)-based thin and ultrathin films that exploits the previously unreported reversibility of a phase transformation between the stoichiometric ferroelectric perovskite and the Pb-deficient non-ferroelectric fluorite to produce single-phase materials with excellent electrical properties while minimizing chemical heterogeneities within the film and interactions with the electrode. Recent work has demonstrated that ferroelectric behavior may persist at length scales below 10 nm, [2][3][4][5] and under certain conditions, perhaps all the way to the unit cell level. [6,7] While these studies suggest the possibility of integrated ferroelectricbased nanodevices, they have so far dealt with model systems using lattice-matched substrates and electrodes onto which epitaxial films were deposited. Because of their high remanent polarization and outstanding electromechanical properties, complex Pb-based materials such as PZT are well-suited for applications including ferroelectric non-volatile memory (FERAM), actuators for micro-/nanoelectromechanical systems (MEMS/NEMS), and piezoelectric energy harvesting.

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“…Especially the mechanisms of nucleation and the transformation from the amorphous film into a crystalline ferroelectric film are still a matter of debate. Among the different proposed models for the microscopic texture selection in PZT films the most prominent approach describes the (111) texture selection on platinized silicon wafers briefly as follows: (111)-oriented PZT nucleates via a transient intermetallic phase (Pt 3 Pb [18], Pt [5][6][7] Pb [19], or Pt [3][4] Pb [20]) because of the almost identical (111) lattice parameters of the two phases PZT and Pt x Pb. It is argued that the PZT(111) texture is controlled by the formation of the intermediate Pt x Pb phase, which arises due to the reducing conditions near the interface caused by the burnout of the surrounding organic material.…”

Section: While Metal-organic Chemical Vapor Deposition (Mocvd) Is a Kmentioning

confidence: 99%

“…4) because the local titanium environment is dominated by the oxygen octahedra rather than by the carbon. augmented plane wave method (in the local density approximation (LDA)) as well as the experimental work from Higuchi et al [63], the peaks labelled by α (531 eV), β (532 eV) (see On the other hand it was figured out by many researchers [18][19][20][21][22][23] that a certain amount of carbon during pyrolysis is important to generate reducing conditions nearby the platinum/PZT interface which leads to the reduction of Pb 2+ to Pb 0 . The latter forms the (111) textured growth promoting Pt x Pb intermetallic phase.…”

Section: Oxygen K Absorption and O K Emission Spectramentioning

confidence: 99%

“…However we found TiO 2 in the rutile phase already in the as-pyrolyzed film at 350°C by the XAS experiments (see above). Thus the (111) PZT nucleation mechanism might be basically explained by a extension of the known intermetallic phase layer model [18][19][20]. If one takes into account that the lattice constant of the (111) Pt x Pb-phase is very similar to that of (111) Pt it is assumed that the detected rutile in the as-pyrolyzed film, could also grow epitaxially in (110) direction on top of this Pt x Pb-alloy (Fig.…”

Section: Proposed Model For Texture Formationmentioning

confidence: 99%

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Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr0.3Ti0.7)O3 thin films by soft X-ray absorption and soft X-ray emission spectroscopy

Schneller

Kohlstedt

Petraru

et al. 2008

J Sol-Gel Sci Technol

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Abstract:Chemical solution deposited (CSD) complex oxide thin films attract considerable interest in various emerging fields as for example, fuel cells, ferroelectric random access memories or coated conductors. In the present paper the results of soft-x-ray spectroscopy between 100 eV and 500 eV on the amorphous to crystalline phase transition of ferroelectric PbZr 0.3 Ti 0.7 O 3 (PZT) thin films are presented. Five CSD samples derived from the same wafer coated with a PZT film pyrolyzed at 350 °C were heat treated at different temperatures between 400 °C and 700 °C. At first the sample were morphologically and electrically characterized. Subsequently the soft-x-ray absorption and emission experiments were performed at the undulator beamline 8.0 of the Advanced Light Source of the Lawrence Berkeley National Laboratory. Soft-x-ray absorption spectra were acquired for the Ti L 2,3 -, O K-, and C K-edge thresholds by using simultaneously the total electron yield (TEY) and total fluorescence yield (TFY) detection methods. For two samples, annealed at 400 °C and 700 °C, respectively, the resonant inelastic soft-x-ray 2 spectroscopy (RIXS) was applied for various excitation energies near the Ti L-, O K-edges. We observed clear evidence of a rutile phase at untypically low temperatures. This rutile phase transforms into the perovskite phase upon increasing annealing temperature. These results are discussed in the framework of current microscopic models of the PZT (111) texture selection.

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TEM characterisation of PZT films prepared by a diol route on platinised silicon substrates

Cited by 48 publications

References 20 publications

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes

Reversibility of the Perovskite‐to‐Fluorite Phase Transformation in Lead‐Based Thin and Ultrathin Films

Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr0.3Ti0.7)O3 thin films by soft X-ray absorption and soft X-ray emission spectroscopy

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TEM characterisation of PZT films prepared by a diol route on platinised silicon substrates

Cited by 48 publications

References 20 publications

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O3 and Pt, Cu and Ag metal electrodes

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O3 and Pt, Cu and Ag metal electrodes

Reversibility of the Perovskite‐to‐Fluorite Phase Transformation in Lead‐Based Thin and Ultrathin Films

Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr0.3Ti0.7)O3 thin films by soft X-ray absorption and soft X-ray emission spectroscopy

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Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes

Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O₃ and Pt, Cu and Ag metal electrodes