Actuation Enhancement of PZT Thin-Film Membrane Actuators via Stress Relief Grooves

2008 ◽  
Author(s):  
Cheng-Chun Lee ◽  
G. Z. Cao ◽  
I. Y. Shen
Keyword(s):  
Thin Film ◽  
Finite Element ◽  
Film Thickness ◽  
Stress Relief ◽  
Design Parameters ◽  
Finite Element Analyses ◽  
Membrane Area ◽  
Aspect Ratios ◽  
Pzt Film ◽  
Pzt Thin Film

Lead Zirconate Titanate Oxide (PbZrxTi1−xO3 or PZT) is a piezoelectric material widely used as sensors and actuators. For microactuators, PZT often appears in the form of thin films to maintain proper aspect ratios. A common design is PZT membrane microactuator, whose actuation portion takes a form of a thin diaphragm driven by a PZT thin film. To maximize actuation displacements, finite element analyses are conducted to identify critical design parameters of the PZT film. In the simulation, a constant driving electric field is maintained and boundary conditions of the PZT film are varied. The finite element analyses lead to two important results. First, the actuator displacement increases as the PZT film thickness increases, but saturates at a critical PZT film thickness. Second, when stress relief grooves are introduced and the PZT film surrounding the membrane area is removed, the actuator displacement increases substantially by at least a factor of 5.

Effects of Corner Frequency on Bandwidth and Resonance Amplitude in Designing PZT Thin-Film Actuators: An Experimental Demonstration

2005 ◽  
Author(s):  
Chia-Che Wu ◽  
Cheng-Chun Lee ◽  
G. Z. Cao ◽  
I. Y. Shen
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Lead Zirconate Titanate ◽  
Corner Frequency ◽  
Frequency Bandwidth ◽  
Resonance Amplitude ◽  
Pzt Film ◽  
Pzt Thin Film ◽  
Wide Range ◽  
Silicon Beam

In the last decade, Lead Zirconate Titanate Oxide (PZT) thin-film actuators have received increasing attention because of their high frequency bandwidth, large actuation strength, fast response, and small size. The PZT film thickness is usually less than several microns as opposed to hundreds of microns for bulk PZT patches that are commercially available. As a result, PZT thin-film actuators pose unique vibration issues that do not appear in actuators with bulk PZT. Two major issues affecting actuator performance are the frequency bandwidth and the resonance amplitude. As an electromechanical device, a PZT thin-film actuator’s bandwidth and resonance amplitude depend not only on the lowest natural frequency ωn of the actuator’s mechanical structure but also on the corner frequency ωc of the actuator’s RC-circuit. For PZT thin-film actuators, the small film thickness implies large film capacitance C and small ωc. When the size of the actuator decreases, frequency ωn increases dramatically. As a result, improper design of PZT thin-film actuators could lead to ωc ≪ ωn substantially reducing the actuator bandwidth and the resonance amplitude. This paper is to demonstrate this phenomenon through calibrated experiments. In the experiments, frequency response functions of a fixed-fixed silicon beam with a 1-μm thick PZT film are measured through use of a laser Doppler vibrometer and a spectrum analyzer. The silicon beam has multiple electrodes with a wide range of resistance R and corner frequency ωc. The experimental results confirm that the actuator bandwidth and resonance amplitude are substantially reduced when ωc ≪ ωn.

Measurement of d15 Shear-Mode Piezoelectric Response in PZT Thin Film

2009 ◽  
Vol 421-422 ◽  
pp. 95-98
Author(s):  
Tsuyoshi Aoki ◽  
Shigeyoshi Umemiya ◽  
Masaharu Hida ◽  
Kazuaki Kurihara
Keyword(s):  
Thin Film ◽  
Fem Analysis ◽  
Active Part ◽  
Piezoelectric Response ◽  
Small Displacement ◽  
Shear Mode ◽  
Mems Devices ◽  
Pzt Film ◽  
Pzt Thin Film ◽  
Piezoelectric Constants

Piezoelectric films using d15 shear-mode can be applied to many useful MEMS devices. The small displacement derived from the d15 shear-mode was directly observed by a SPM measurement. An isolated PZT(52/48) active part having a pair of driving Cu electrodes was processed in a 5 m-thick sputtering film. The displacement measurement of the active part and its FEM analysis suggested that the estimated d15 piezoelectric constant of the film was 590 pm/V. And, the d31 value of the film was -120 pm/V measured by a conventional cantilever method. The obtained piezoelectric constants of the PZT film are near those of bulk.

scholarly journals Synchrotron X-ray Microdiffraction Images of Polarization Switching in Epitaxial PZT Capacitors with Pt and SrRuO3 Top Electrodes

2003 ◽  
Vol 784 ◽  
Author(s):  
Dal-Hyun Do ◽  
Dong Min Kim ◽  
Chang-Beom Eom ◽  
Eric M. Dufresne ◽  
Eric D. Isaacs ◽  
...  
Keyword(s):  
Thin Film ◽  
Bottom Electrode ◽  
Sputter Deposition ◽  
Ferroelectric Polarization ◽  
X Rays ◽  
X Ray ◽  
Pzt Film ◽  
Thin Film Capacitors ◽  
Pzt Thin Film ◽  
Switchable Polarization

ABSTRACTThe evolution of stored ferroelectric polarization in PZT thin film capacitors was imaged using synchrotron x-ray microdiffraction with a submicron-diameter focused incident x-ray beam. To form the capacitors, an epitaxial Pb(Zr,Ti)O3 (PZT) thin film was deposited on an epitaxially-grown conductive SrRuO3 (SRO) bottom electrode on a SrTiO3 (STO) (001) substrate. Polycrystalline SRO or Pt top electrodes were prepared by sputter deposition through a shadow mask and subsequent annealing. The intensity of x-ray reflections from the PZT film depended on the local ferroelectric polarization. With 10 keV x-rays, regions of opposite polarization differed in intensity by 26% in our PZT capacitor with an SRO top electrode. Devices with SRO electrodes showed just a 25% decrease in the remnant polarization after 107 switching cycles. In devices with Pt top electrodes, however, the switchable polarization decreased a by 70% after only 5×104 cycles.

scholarly journals Reducing car audio button noise while maintaining tactile quality

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775259
Author(s):  
Hyo-Chan Kwon ◽  
Chang-Hee Cho ◽  
Cheong-Wu Nam ◽  
Soo-Won Chae ◽  
Seong-Yun Seo ◽  
...  
Keyword(s):  
Finite Element ◽  
Design Parameters ◽  
Model Parameters ◽  
Finite Element Analyses ◽  
Passenger Cars ◽  
Cabin Noise ◽  
Prototype Test ◽  
Subsequent Response ◽  
Car Audio ◽  
Improved Design

Recently, interior noise levels of passenger cars have been significantly reduced. The reduction of major cabin noise led to the recognition of small noises that are previously unnoticed. Specifically, the button noises of electrical devices in passenger compartments have been identified as belonging to this category of noise. The aim of this study is to improve the auditory quality of a car audio button while maintaining its tactile quality that is familiar to users. The tactile and auditory qualities can be described by the load versus stroke characteristics and the operation noise level. For buttons with rubber domes, the buckling behavior of the domes governs the tactile and auditory qualities. To preserve the tactile quality, the sensitivity of load versus stroke characteristics to each of the eight identified parameters is obtained from the finite element analyses using model parameters varied by ±10%. Four parameters to which the tactile quality was insensitive are selected. To identify the contributions of these four design parameters to auditory quality, finite element analyses were performed in conjunction with design of experiments. The improved design obtained by the subsequent response surface methodology optimization was validated by a prototype test with a 12 dBA reduction in noise.

Experimental Evaluation of the Probe Test for Measuring Thin Film Adhesion

2003 ◽  
Author(s):  
David A. Dillard ◽  
Caleb Scott ◽  
Kris Mount ◽  
Dingying Xu ◽  
Kai-Tak Wan ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Finite Element ◽  
Experimental Evaluation ◽  
Polymeric Coating ◽  
Finite Element Analyses ◽  
Film Adhesion ◽  
Thin Film Adhesion ◽  
Probe Test ◽  
Interfacial Fracture Energy

A probe test is proposed to quantify the adhesion of thin films and coatings. Using a micromanipulator, a tungsten probe is advanced into the edge of a polymeric coating. Debonds initiate at the loading point and propagate into semicircular cracks at the interface as the probe slides under the coating. The size of the debond is related to the interfacial fracture energy; poorer adhesion results in larger debonds for a given probe displacement. Approximate closed-form and finite element analyses of the geometry have been conducted, along with a significant number of experiments on as-produced and environmentally-conditioned specimens. The technique is showing considerable promise for characterizing coating adhesion, and has certain advantages over existing techniques for certain application.

Application of ASME Code Section XI Appendix L Using 3-D Finite Element Analyses

2020 ◽  
Author(s):  
Charles Fourcade ◽  
Minji Fong ◽  
James Axline ◽  
Do Jun Shim ◽  
Chris Lohse ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Growth ◽  
Cyclic Stress ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Aspect Ratios ◽  
Flaw Tolerance ◽  
Asme Code ◽  
Stress Ratios

Abstract As part of a fatigue management program for subsequent license renewal, a flaw tolerance evaluation based on ASME Code, Section XI, Appendix L may be performed. The current ASME Code, Section XI, Appendix L flaw tolerance methodology requires determination of the flaw aspect ratio for initial flaw size calculation. The flaw aspect ratios listed in ASME Section XI, Appendix L, Table L-3210-2, for austenitic piping for example, are listed as a function of the membrane-to-gradient cyclic stress ratio. The Code does not explicitly describe how to determine the ratio, especially when utilizing complex finite element analyses (FEA), involving different loading conditions (i.e. thermal transients, piping loads, pressure, etc.). The intent of the paper is to describe the methods being employed to determine the membrane-to-gradient cyclic stress ratios, and the corresponding flaw aspect ratios (a/l) listed in Table L-3210-2, when using finite element analysis methodology. Included will be a sample Appendix L evaluation, using finite element analysis of a pressurized water reactor (PWR) pressurizer surge line, including crack growth calculations for circumferential flaws in stainless steel piping. Based on this example, it has been demonstrated that, unless correctly separated, the membrane-to-gradient cyclic stress ratios can result in extremely long initial flaw lengths, and correspondingly short crack growth durations.

PZT Thin Films Deposited by RF Magnetron Sputtering

2013 ◽  
Vol 302 ◽  
pp. 8-13
Author(s):  
Shun Fa Hwang ◽  
Wen Bin Li
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Annealing Temperature ◽  
Bottom Electrode ◽  
Rf Sputtering ◽  
Rf Magnetron Sputtering ◽  
Pzt Thin Films ◽  
Pzt Film ◽  
Pzt Thin Film

PZT thin film was fabricated by using RF-sputtering process, and platinum was used as bottom electrodes. The sputtering gases were Ar：O2＝25：0 sccm, Ar：O2＝20：5 sccm, or Ar：O2＝15：10 sccm. After sputtering, the PZT film was annealed for 5 minutes under O2 gas environment and at the temperature of 600 0C, 650 0C, 700 0C or 750 0C. To judge the quality of the deposited PZT film, its physical properties and electric properties were evaluated. The results indicate that the best crystallization temperature of PZT thin film is about 700 0C. Also, the roughness of the PZT thin film becomes larger with the increasing of annealing temperature. By adding more oxygen in the sputtering gas, one could have better crystallization of the PZT film. As for the electrical properties, the leakage current of PZT thin film increases with the increasing of annealing temperature. Furthermore, the ferroelectric property is affected by the crystallization amount of perovskite, the thickness of PZT thin film, and the diffusion situation between the bottom electrode and the PZT film.

A Finite Element Study on the Nanoindentation of Thin Films

2000 ◽  
Vol 649 ◽  
Author(s):  
Xi Chen ◽  
Joost J. Vlassak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Finite Element ◽  
Film Thickness ◽  
Substrate Effect ◽  
The Finite Element Method ◽  
Effect Factor ◽  
Pile Up ◽  
Key Factor ◽  
Elastic Mismatch

ABSTRACTNanoindentation is a technique commonly used for measuring thin film mechanical properties such as hardness and stiffness. Typically, shallow indentations with contact depths less than 10-20% of the film thickness are used to ensure that measurements are not affected by the presence of the substrate. In this study, we have used the finite element method to investigate the effect of substrate and pile-up on hardness and stiffness measurements of thin film systems. We find that: i) for soft films on hard substrates, the hardness is independent of the substrate as long as the indentation depth is less than 50% of the film thickness; ii) as soon as the hardness exceeds that of the substrate, the substrate effect becomes significant, even for indentations as shallow as 5% of the film thickness; iii) if the film is at least 40 times harder than the substrate, the plastic zone is mostly confined to the substrate while the film conforms to the deformed substrate by bending. We define a substrate effect factor and construct a map that may be useful in the interpretation of indentation measurements on thin films. It is found that the yield stress mismatch is a key factor characterizing the hardness of thin film system, and the elastic mismatch is important when making stiffness measurements. The results obtained in this study are very useful when it is difficult to avoid the influence of the substrate on the measurements.

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