Effective Direct Piezoelectric Constants in Epitaxial Ferroelectric Films as MEMS Sensors

2005 ◽  
Vol 881 ◽  
Author(s):  
Jun Ouyang ◽  
R. Ramesh ◽  
A. L. Roytburd
Keyword(s):  
Thin Films ◽  
Orientation Dependence ◽  
Ferroelectric Thin Films ◽  
Piezoelectric Constant ◽  
Mems Sensors ◽  
Ferroelectric Films ◽  
Si Substrates ◽  
Mems Sensor ◽  
Sensor Devices ◽  
Piezoelectric Constants

AbstractFollowing our previous work on the converse piezoelectric constant- in epitaxial ferroelectric films for MEMS actuator applications, the orientation dependence of the direct piezoelectric constants , and are generally formulated, which can help to predict and optimize the performance of piezoelectric MEMS sensor devices based on ferroelectric thin films. Numerical results are obtained and discussed for Pb(ZrxTi1-x)O3 thin films grow on Si substrates with various compositions and structures.

Effects of Sputter-Deposited LaNiO3 Electrode on the Deposition and Properties of Ferroelectric Thin Films

1996 ◽  
Vol 433 ◽  
Author(s):  
T. B. Wu ◽  
J. M. Wu ◽  
C. M. Wu ◽  
M. J. Shyu ◽  
M. S. Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Processing Condition ◽  
Fatigue Property ◽  
Rf Magnetron Sputtering ◽  
Ferroelectric Films ◽  
Si Substrates ◽  
Sputter Deposited

AbstractHighly (100)-textured thin film of metallic LaNiO3 (LNO) was grown on the Pt/Ti/SiO2/Si substrates by rf magnetron sputtering at ˜300°C, which was used as a bottom electrode to prepare highly (100)-textured ferroelectric films. Examples on the deposition of PbTiO3, (Pbl−xLax)TiO3, Pb(Zr0.53Ti0.47)O3, Pb[(Mg1/3Nb2/3)1−xTix]O3, and (Ba1−xSrx)TiO3 thin films by rf magnetron sputtering or sol-gel method are shown. A reduction of temperature for perovskite phase formation can be achieved, especially for those difficult to crystallize. The surface roughness of the ferroelectric films is also improved as compared to that of films deposited on conventional Pt electrode. Although the electrical properties of the ferroelectric films are affected by the out-diffusion of LNO when a higher temperature was used in the preparation of the films, under an appropriate processing condition, the highly (100)-textured films can have satisfactory electrical characteristics for application. Moreover, the polarization-fatigue property can be also improved by the use of LNO electrode.

Influence of Excess Potassium on Structural and Ferroelectric Properties of Lead-Free Bi0.5K0.5TiO3 Thin Films

2021 ◽  
Vol 21 (4) ◽  
pp. 2681-2686
Author(s):  
Nguyen Ngoc Minh ◽  
Bui Van Dan ◽  
Nguyen Duc Minh ◽  
Guus Rijnders ◽  
Ngo Duc Quan
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Single Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Chemical Solution ◽  
Ferroelectric Films ◽  
Solution Deposition ◽  
Si Substrates ◽  
Excess Amount

Lead-free Bi0.5K0.5TiO3 (BKT) ferroelectric films were synthesized on Pt/Ti/SiO2/Si substrates via the chemical solution deposition. The influence of the excess potassium on the microstructures and the ferroelectric properties of the films was investigated in detail. The results showed that the BKT films have reached the well-crystallized state in the single-phase perovskite structure with 20 mol.% excess amount of potassium. For this film, the ferroelectric properties of the films were significantly enhanced. The remnant polarization (Pr) and maximum polarization (Pm) reached the highest values of 9.4 μC/cm2 and 32.2 μC/cm2, respectively, under the electric field of 400 kV/cm.

Preparation of Bi2SiO5-SrBi2Ta2O9 Ferroelectric Thin Films by RF Magnetron Sputtering

2002 ◽  
Vol 748 ◽  
Author(s):  
Shin Kikuchi ◽  
Hiroshi Ishiwara
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Remnant Polarization ◽  
Rf Magnetron Sputtering ◽  
Ferroelectric Thin Films ◽  
Ferroelectric Films ◽  
Typical Composition

ABSTRACTSi-added SrBi2Ta2O9 (SBT) ferroelectric films were prepared by RF magnetron sputtering on a Pt/Ti/SiO2/Si (100) structure. The films were deposited at temperatures below 100°C for preventing Bi evaporation and crystallized at 800°C in air. A typical composition was Sr0.79Bi2.37Ta2.00Si0.2Ox. The remnant polarization value(2Pr) of the Si-added SBT film was 16C/cm2 and leakage current density was 5×10-8A/cm2. The current density was significantly decreased by adding Si atoms.

Ferroelectric thin films on silicon carbide for next-generation nonvolatile memory and sensor devices

2004 ◽  
Vol 469-470 ◽  
pp. 444-449 ◽  
Author(s):  
Mikael Östling ◽  
Sang-Mo Koo ◽  
Carl-Mikael Zetterling ◽  
Sergey Khartsev ◽  
Alex Grishin
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Nonvolatile Memory ◽  
Ferroelectric Thin Films ◽  
Next Generation ◽  
Sensor Devices

Ion Modification for Improvement of Electrical Properties of Perovskite-based Ferroelectric Thin Films Fabricated by Chemical Solution Deposition Method

2005 ◽  
Vol 902 ◽  
Author(s):  
Hiroshi Uchida ◽  
Shintaro Yasui ◽  
Risako Ueno ◽  
Hiroshi Nakaki ◽  
Ken Nishida ◽  
...  
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Electrical Properties ◽  
Chemical Solution Deposition ◽  
Perovskite Oxides ◽  
Ferroelectric Thin Films ◽  
Chemical Solution ◽  
Ferroelectric Films ◽  
Solution Deposition ◽  
Crystal Anisotropy

AbstractIon modification for various perovskite-based ferroelectric thin films using rare-earth cations was attempted for improving the electrical properties. Strategy for controlling the electrical properties is mainly based on two concepts, that is, (i) substituting the volatile cations such as Pb2+ and Bi3+, and (ii) controlling the crystal anisotropy of perovskite unit cell. In this study, the influences of ion-modification conditions (i.e., amount, species and occupying site of substituent cations) on the electrical properties of perovskite-based ferroelectric films fabricated by a chemical solution deposition were investigated. Substituting volatile cations in simple-perovskite oxides, such Pb2+ in Pb(Zr,Ti)O3 and Bi3+ in BiFeO3, for the rare-earth cations like La3+ and Nd3+ reduced the leakage current density of these films due to suppressing the metal and / or oxygen vacancies, as well as in layered-perovskite oxides, such as Bi4Ti3O12 films [i.e., strategy (i)]. Also, crystal anisotropy of perovskite-based oxides could controlled by varying the species and the occupying site of substituent cations [i.e., strategy (ii)]; for example, the crystal anisotropy of Pb(Zr,Ti)O3 lattice was elongated by Ti- and Zr-site (B-site) substitution using rare-earth cations whose ionic radii locate on the smaller part of rare-earth series (such as Y3+, Dy3+), that resulted in enhancing the spontaneous polarization. We concluded that the strategy for controlling the electrical property mentioned in this study would be applicable for a various kind of perovskite-based ferroelectric films.

(100) Oriented Sputter-deposited Pt Thin Films on MgO/Fe Composite Bilayers using SiO2/Si substrates With Addition of O2 During Pt Sputtering

2010 ◽  
Vol 1255 ◽  
Author(s):  
Shigeki Nakagawa ◽  
Hiroshi Nakano ◽  
Yuji Murashima ◽  
Kazuki Komaki ◽  
Tatsuro Matsumoto ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Surface Energy ◽  
Bottom Electrode ◽  
Oxide Films ◽  
Oxide Thin Films ◽  
Ferroelectric Films ◽  
Si Substrates ◽  
20 Nm ◽  
Perovskite Type

AbstractPerovskite type oxide thin films have attracted a lot of attention, because they are essential materials which will be used for various electric devices such as ferroelectric random access memory (FeRAM) and tunable filter devices. When the materials are used for such capacitive devices, bottom electrode layers for oxide films are very important, since they significantly affect the crystallinity of the oxide films. Platinum (Pt) is one of the well known bottom electrode materials used for the oxide thin films. Pt provides also better nucleation sites for such perovskite materials due to small lattice misfit. Since dielectric properties of ferroelectric films are originated from the displacement of ions in a crystal along the c-axis direction, c-axis oriented ferroelectric thin films are required to attain better dielectric properties. (100) oriented Pt layers are required to attain c-axis oriented perovskite type ferroelectric films. In our previous report, we succeeded in preparing (100)-oriented Pt thin films with thickness of 20 nm on SiO2/Si substrate at substrate temperature Ts above 400 °C using MgO (100) buffer layers which deposited on Fe (100) seed layers. However, the growth of Pt(111) texture appeared when the thickness was increased from 20 nm to 100 nm, since (100) texture has relatively higher surface energy than (111) closely packed texture for Pt surface. It suggested that surface energy of the films changed during the deposition. In order to keep the surface energy, addition of O2 gas was performed during Pt deposition. Pt thin films with (100) preferred orientation with thickness above 100 nm were deposited on the (100) oriented MgO layer prepared on very thin seed Fe layers deposited on SiO2/Si substrates at Ts of 500 °C by facing-targets sputtering. It was also succeeded to attain (100) oriented perovskite oxide layer when they were deposited on the Pt(100)/Mg(100)/Fe/SiO2/Si underlayer.

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