Residual Stress Control to Optimize Pzt Mems Performance

2002 ◽  
Vol 741 ◽  
Author(s):  
M.S. Kennedy ◽  
D.F. Bahr ◽  
C.D. Richards ◽  
R.F. Richards
Keyword(s):  
Residual Stress ◽  
Lead Zirconate Titanate ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Membrane Performance ◽  
Boron Doped ◽  
Pzt Film ◽  
Bulge Testing

ABSTRACTFlexing piezoelectric membranes can be used to convert mechanical energy to electrical energy. The overall deflection of individual membranes is impacted by the residual stress in the system. Membranes comprised of silicon dioxide, Ti/Pt, lead- zirconate- titanate (PZT), and TiW/Au layers deposited on a micromachined boron doped silicon wafer were examined for both morphology and residual stress. By characterizing the membrane residual stress induced during processing with x-ray diffraction, wafer curvature, and bulge testing and identifying methods to reduce stress, the membrane performance and reliability can be optimized. For Zr:Ti ratios of 52:48, the residual stress in the PZT was 350 MPa tensile, with an overall effective stress in the composite membrane of 150 MPa. A reduction of stress was accomplished by changing the PZT chemistry to 40:60 Zr:Ti in the PZT to obtain a stress in the PZT of 160 MPa tensile and an overall effective membrane stress of 100 MPa. The crystallization of the 52:48 PZT film at 700 °C causes a 28% reduction in the thickness of the film.

Relationships Between Microstructure and Reliability in Pzt Mems

2001 ◽  
Vol 666 ◽  
Author(s):  
B.W. Olson ◽  
L.M. Randall ◽  
C.D. Richards ◽  
R.F. Richards ◽  
D.F. Bahr
Keyword(s):  
Grain Size ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Electrical Energy ◽  
Lead Zirconate ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Processing Route ◽  
Bulge Testing ◽  
Sol Gel Process

ABSTRACTPiezoelectric oxide films, such as lead zirconate titanate (PZT), are now being integrated into MEMS applications. Many PZT derived systems are deposited using a sol-gel process, which can be used in a microelectronics processing route using spin coating as the deposition method. An application of interest for PZT films is in power generation, where a flexing membrane is used to transform mechanical to electrical energy. The current study was undertaken to identify the relationships between the processing, microstructure, and mechanical reliability of these films. Films were deposited onto both monolithic and bulk micromachined platinized silicon wafers using standard sol-gel chemistries, with roughness and grain size tracked using electron and scanning probe microscopy. Mechanical properties were evaluated in a dynamic bulge testing apparatus. Grain size variations in the Pt film between 35 and 125 nm are shown to have little effect on grain size of the subsequent PZT film and the adhesion of the PZT to the Pt film. Only the Pt film with 125 nm grains was shown to undergo any significant interfacial fracture. Fatigue tests suggest film lifetime is primarily limited by the number of pre- existing flaws in the film from processing. Reducing the microcrack density has been shown to produce films and devices that fail at strains of 1.4% and have mechanical fatigue lifetimes in excess of 100 million cycles at strains simulating the operating conditions.

scholarly journals Hollow Piezoelectric Ceramic Fibers for Energy Harvesting Fabrics

2013 ◽  
Vol 8 (1) ◽  
pp. 155892501300800
Author(s):  
François M. Guillot ◽  
Haskell W. Beckham ◽  
Johannes Leisen
Keyword(s):  
Energy Harvesting ◽  
Lead Zirconate Titanate ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Lead Zirconate ◽  
Ceramic Fibers ◽  
Power Sources ◽  
Electromechanical Performance ◽  
Alternative Power

In the past few years, the growing need for alternative power sources has generated considerable interest in the field of energy harvesting. A particularly exciting possibility within that field is the development of fabrics capable of harnessing mechanical energy and delivering electrical power to sensors and wearable devices. This study presents an evaluation of the electromechanical performance of hollow lead zirconate titanate (PZT) fibers as the basis for the construction of such fabrics. The fibers feature individual polymer claddings surrounding electrodes directly deposited onto both inside and outside ceramic surfaces. This configuration optimizes the amount of electrical energy available by placing the electrodes in direct contact with the surface of the material and by maximizing the active piezoelectric volume. Hollow fibers were electroded, encapsulated in a polymer cladding, poled and characterized in terms of their electromechanical properties. They were then glued to a vibrating cantilever beam equipped with a strain gauge, and their energy harvesting performance was measured. It was found that the fibers generated twice as much energy density as commercial state-of-the-art flexible composite sensors. Finally, the influence of the polymer cladding on the strain transmission to the fiber was evaluated. These fibers have the potential to be woven into fabrics that could harvest mechanical energy from the environment and could eventually be integrated into clothing.

Study of PZT Film Stress in Multilayer Structures for MEMS Devices

1999 ◽  
Vol 605 ◽  
Author(s):  
E. Zakar ◽  
M. Dubey ◽  
R. Polcawich ◽  
B. Piekarski ◽  
R. Piekarz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Film Stress ◽  
Dielectric Films ◽  
Mems Devices ◽  
Annealing Conditions ◽  
Pzt Film ◽  
Final Stress

AbstractResidual stress in the multilayer Si/Dielectric/Pt/PZT/Pt stack was measured as a function of annealing conditions, sol-gel derived PZT (Lead Zirconate Titanate -52/48) thickness, SiO2 and/or Si3N4 dielectric films thickness. Residual stress in the Si3N4 layer varied from -201 to +1275 MPa and from -430 to + 511 MPa in the Si02 layer. Furnace annealing of the bottom Pt film reduced the stress over rapid thermal annealing (RTA). Stress due to PZT films was the controlling factor for the final stress of the stack. Upon increasing PZT thickness, stress became less tensile for Si3N4 dielectric and more tensile for Si02. The deposition of the top Pt on PZT followed by RTA at 300°C in nitrogen had a minimal effect on the final stress of the stack. The average tensile stress for the Si/Si02 /Pt/PZT/Pt and Si/Si3N4/Pt/PZT/Pt stacks was 140 ± 25 and 476±235 MPa respectively.

Improvement of Ferroelectric Properties of Lead Zirconate Titanate Thin Films by Ion-substitution using Rare-earth Cations

2004 ◽  
Vol 830 ◽  
Author(s):  
Hiroshi Nakaki ◽  
Hiroshi Uchida ◽  
Shoji Okamoto ◽  
Shintaro Yokoyama ◽  
Hiroshi Funakubo ◽  
...  
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Lead Zirconate Titanate ◽  
Ferroelectric Property ◽  
Ferroelectric Properties ◽  
Lead Zirconate ◽  
Crystal Anisotropy ◽  
Pzt Film ◽  
Zirconate Titanate ◽  
Ion Substitution

ABSTRACTRare-earth-substituted tetragonal lead zirconate titanate thin films were synthesized for improving the ferroelectric property of conventional lead zirconate titanate. Thin films of Pb1.00REx (Zr0.40Ti0.60)1-(3x /4)O3 (x = 0.02, RE = Y, Dy, Er and Yb) were deposited on (111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution deposition (CSD). B-site substitution using rare-earth cations described above enhanced the crystal anisotropy, i.e., ratio of PZT lattice parameters c/a. Remanent polarization (Pr) of PZT film was enhanced by Y3+-, Dy3+- and Er3+-substitution from 20 μC/cm2 up to 26, 25 and 26 μC/cm2 respectively, while ion substitution using Yb3+ degraded the Pr value down to 16 μC/cm2. These films had similar coercive fields (Ec) of around 100 kV/cm. Improving the ferroelectric property of PZT film by rare-earth-substitution would be ascribed to the enhancement of the crystal anisotropy. We concluded that ion substitution using some rare-earth cations, such as Y3+, Dy3+ or Er3+, is one of promising technique for improving the ferroelectric property of PZT film.

PIEZOELECTRIC PROPERTIES OF PZT FILMS PREPARED BY HYDROTHERMAL METHOD

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3805-3810 ◽  
Author(s):  
NOBUYOSHI FUJIWARA ◽  
KAZUHIRO KUSUKAWA ◽  
KHAIRUNISAK ABDUL RAZAK ◽  
WEI GAO
Keyword(s):  
Hydrothermal Method ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Properties ◽  
Compressive Loading ◽  
Pure Titanium ◽  
Lead Zirconate ◽  
Loading Frequency ◽  
X Ray Diffraction ◽  
Pzt Films ◽  
Transverse Effect

Lead zirconate titanate (PZT) thin films of 5 μm thick were produced by a hydrothermal method on pure titanium substrates. ZrOCl 2-8 H 2 O , Pb ( NO 3)2 and TiO 2 were used as precursors and KOH as a promoter. The hydrothermal synthesis of PZT includes nucleation and crystal growth processes at 120°C or 140°C. The crystallization states were investigated by using scanning electron microscopy and X-Ray diffraction. Piezoelectric properties were evaluated from unimorph cantilever type actuators made of the films. The relationships between the deflection of the actuator due to piezoelectric transverse effect and applied electric field in the direction of thickness of the films showed good linearity. The output voltage from the films under cyclic compressive loading increased with increasing loading frequency, and is saturated at 10 Hz. The PZT films produced by the present methods are satisfactory as a smart material, and are better than the films produced using TiCl 4 as Ti precursor.

Research of the PZT Polarization for Deformable Mirror

2014 ◽  
Vol 609-610 ◽  
pp. 1331-1335
Author(s):  
Jun Jie Chen ◽  
Ying Liu ◽  
Jian Qiang Ma ◽  
Ji Cong Deng ◽  
Bao Qing Li ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Coefficient ◽  
Lead Zirconate ◽  
Deformable Mirror ◽  
Pzt Film ◽  
Zirconate Titanate

This paper demonstrates that the deformation of the piezoelectric deformable mirror (DM) is proportional to the transverse piezoelectric coefficient of the lead zirconate titanate (PZT) by the theoretical analysis. The optimal polarization conditions were obtained by experiments to optimize the performance of the DM. After the optimal polarization, the transverse piezoelectric coefficient of the PZT film increases from 350 pm/V to 431 pm/V, which will improve the deformation of the DM.

Contribution from Ferroelastic Domain Switching Detected Using X-ray Diffraction toR-Curves in Lead Zirconate Titanate Ceramics

2001 ◽  
Vol 84 (12) ◽  
pp. 2921-2929 ◽  
Author(s):  
Alexandre E. Glazounov ◽  
Hans Kungl ◽  
Jan-Thorsten Reszat ◽  
Michael J. Hoffmann ◽  
Arnd Kolleck ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Domain Switching ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconate Titanate ◽  
Titanate Ceramics

Fabrication and Characterization of Sol-Gel Derived PZT/WO3 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 369-372 ◽  
Author(s):  
T. Sreesattabud ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Rhombohedral Phase ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
Materials Used ◽  
Phase Characterization ◽  
Gel Processing

Lead zirconate titanate/tungsten oxide (PZT/WO3) ceramics were prepared from the powders synthesized by a modified triol sol-gel processing method. In this study, the starting materials used for synthesis of PZT-sol were zirconium (IV) propoxide, titanium (IV) isopropxide, lead (II) acetate trihydrate and 1,1,1,- tris (hydroxymethyl) ethane. To prepare PZT/xWO3 powders (where x = 0, 0.5, 1 and 3 wt%), nano-sized WO3 was ultrasonically dispersed and mixed with the PZT sol, dried and calcined at 600°C for 4 h. X-ray diffraction results indicated that fully crystallized powders were obtained. Phase characterization suggested that at high WO3 concentration, the reaction between PZT and WO3 occurred during the calcination process. To prepare PZT/xWO3 ceramics, the powders were pressed and sintered at 1100°C for 6 h. Phase characterization by XRD indicated that the content of WO3 significantly affected tetragonal-to-rhombohedral phase transition. Microstructure of thermally etched samples showed that increasing the content of WO3 decreased grain size of the ceramics.

scholarly journals Hydrothermal synthesis and characteristics of lanthanumdoped pb(Zr₀.₆₅Ti ₀.₃₅)O₃ ceramics

2021 ◽  
Vol 8 (3) ◽  
pp. 14-19
Author(s):  
Thuy Nguyen Thanh ◽  
Tung Nguyen Van ◽  
Hung Nguyen Trong ◽  
Minh Cao Duy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Reaction Temperature ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Influence Of Ph ◽  
Scanning Electron

Lanthanum-doped lead zirconate titanate (PLZT) powders were synthesized using thehydrothermal method. The influence of pH, reaction temperature and time, lanthanum concentration on the formation and characteristics of PLZT were investigated. Obtained powders were investigated using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) techniques and a dielectric analyzer. The results showed that           Pb1-xLax(Zr0.65Ti0.35)O3 with x= 0.0 – 0.1 were well formed under conditions: pH≥13, reaction time of 12hrs, reaction temperature of 180oC. Dielectric constant of PLZT is higher than PZT. The grain size of the PLZT is found to be 1–3.5 µm.

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