Improving PZT Thin Film Texture Through Pt Metallization and Seed Layers

2011 ◽  
Vol 1299 ◽  
Author(s):  
L.M. Sanchez ◽  
D.M. Potrepka ◽  
G.R. Fox ◽  
I. Takeuchi ◽  
R.G. Polcawich
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Seed Layer ◽  
Film Growth ◽  
Past Research ◽  
Lead Zirconate ◽  
Research Activities ◽  
Pzt Thin Film ◽  
Seed Layers

ABSTRACTLeveraging past research activities in orientation control of lead zirconate titanate (PZT) thin films [1,2], this work attempts to optimize those research results using the fabrication equipment at the U.S. Army Research Laboratory so as to achieve a high degree of {001}- texture and improved piezoelectric properties. Initial experiments examined the influence of Ti/Pt and TiO2/Pt thins films used as the base-electrode for chemical solution deposition PZT thin film growth. In all cases, the starting silicon substrates used a 500 nm thermally grown silicon dioxide. The Pt films were sputter deposited onto highly textured titanium dioxide films grown by a thermal oxidation process of a sputtered Ti film [3]. The second objective targeted was to achieve highly {001}-textured PZT using a seed layer of PbTiO3 (PT). A comparative study was performed between Ti/Pt and TiO2/Pt bottom electrodes. The results indicate that the use of a highly oriented TiO2 led to highly {111}-textured Pt, which in turn improved both the PT and PZT orientations. Both PZT (52/48) and (45/55) thin films with and without PT seed layers were deposited and examined via x-ray diffraction methods (XRD) as a function of annealing temperature. As expected, the PT seed layer provides significant improvement in the PZT {001}-texture while suppressing the {111}-texture of the PZT. Improvements in the Lotgering factor (f) were observed upon comparison of the original Ti/Pt/PZT process (f=0.66) with samples using the PT seed layer as a template, Ti/Pt/PT/PZT (f=0.87), and with films deposited onto the improved Pt electrodes, TiO2/Pt/PT/PZT (f=0.96).

Oxygen transport during annealing of Pb(Zr,Ti)O3 thin films in O2 gas and its effect on their conductivity

2001 ◽  
Vol 16 (10) ◽  
pp. 3005-3008 ◽  
Author(s):  
F. Ayguavives ◽  
B. Agius ◽  
B. EaKim ◽  
I. Vickridge
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Leakage Current ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Low Leakage ◽  
Pzt Film ◽  
Low Leakage Current ◽  
Pzt Thin Film ◽  
Current Densities

Lead zirconate titanate (PZT) thin films were deposited in a reactive argon/oxygen gas mixture by radio-frequency-magnetron sputtering. The use of a metallic target allows us to control the oxygen incorporation in the PZT thin film and also, using oxygen 18 as a tracer, to study the oxygen diffusion in the thin films. Electrical properties and crystallization were optimized with a 90-nm PZT thin film grown on RuO2 electrodes. These PZT films, annealed with a very modest thermal budget (550 °C) show very low leakage current densities (J = 2 × 10−8 A/cm2 at 1 V). In this article we show that a strong correlation exists between the oxygen composition in the PZT film and the leakage current density.

Measurements of Piezoelectric Coefficient d33 of Lead Zirconate Titanate Thin Films Using a Mini Force Hammer

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Qing Guo ◽  
G. Z. Cao ◽  
I. Y. Shen
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Coefficient ◽  
Lead Zirconate ◽  
New Method ◽  
Impulsive Force ◽  
Pzt Thin Films ◽  
Zirconate Titanate ◽  
Pzt Thin Film

Lead zirconate titanate (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. One major challenge encountered is accurate measurement of piezoelectric coefficients of PZT thin films. In this paper, we present a simple, low-cost, and effective method to measure piezoelectric coefficient d33 of PZT thin films through use of basic principles in mechanics of vibration. A small impact hammer with a tiny tip acts perpendicularly to the PZT thin-film surface to generate an impulsive force. In the meantime, a load cell at the hammer tip measures the impulsive force and a charge amplifier measures the responding charge of the PZT thin film. Then the piezoelectric coefficient d33 is obtained from the measured force and charge based on piezoelectricity and a finite element modeling. We also conduct a thorough parametric study to understand the sensitivity of this method on various parameters, such as substrate material, boundary conditions, specimen size, specimen thickness, thickness ratio, and PZT thin-film material. Two rounds of experiments are conducted to demonstrate the feasibility and accuracy of this new method. The first experiment is to measure d33 of a PZT disk resonator whose d33 is known. Experimental results show that d33 measured via this method is as accurate as that from the manufacturer's specifications within its tolerance. The second experiment is to measure d33 of PZT thin films deposited on silicon substrates. With the measured d33, we predict the displacement of PZT thin-film membrane microactuators. In the meantime, the actuator displacement is measured via a laser Doppler vibrometer. The predicted and measured displacements agree very well validating the accuracy of this new method.

Correlations Among Degradations in Lead Zirconate Titanate thin Film Capacitors

1993 ◽  
Vol 310 ◽  
Author(s):  
In K. Yoo ◽  
Seshu B. Desu ◽  
Jimmy Xing
Keyword(s):  
Thin Film ◽  
Leakage Current ◽  
Lead Zirconate Titanate ◽  
Oxygen Vacancies ◽  
Lead Zirconate ◽  
Electrical Degradation ◽  
Zirconate Titanate ◽  
Thin Film Capacitors ◽  
Pzt Thin Film ◽  
Degradation Properties

AbstractMany attempts have been made to reduce degradation properties of Lead Zirconate Titanate (PZT) thin film capacitors. Although each degradation property has been studied extensively for the sake of material improvement, it is desired that they be understood in a unified manner in order to reduce degradation properties simultaneously. This can be achieved if a common source(s) of degradations is identified and controlled. In the past it was noticed that oxygen vacancies play a key role in fatigue, leakage current, and electrical degradation/breakdown of PZT films. It is now known that space charges (oxygen vacancies, mainly) affect ageing, too. Therefore, a quantitative ageing mechanism is proposed based on oxygen vacancy migration under internal field generated by either remanent polarization or spontaneous polarization. Fatigue, leakage current, electrical degradation, and polarization reversal mechanisms are correlated with the ageing mechanism in order to establish guidelines for simultaneous degradation control of PZT thin film capacitors. In addition, the current pitfalls in the ferroelectric test circuit is discussed, which may cause false retention, imprint, and ageing.

Effect of Annealing Treatment on PZT Thin Fiilm Properties Using Oxygen 18 Depth Profiling Technique

1998 ◽  
Vol 541 ◽  
Author(s):  
F. Ayguavives ◽  
B. Ea-Kim ◽  
B. Agius ◽  
I. Vickridge ◽  
A. I. Kingon
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Plasma Deposition ◽  
Annealing Treatment ◽  
Nuclear Reaction Analysis ◽  
Nominal Composition ◽  
Pzt Thin Films ◽  
Pzt Thin Film ◽  
Metallic Target

AbstractLead zirconate titanate (PZT) thin films have been deposited in a reactive argon/oxygen gas mixture from a metallic target of nominal composition Pb1.1(Zr0.4Ti0.6)O3 by rf magnetron sputtering on Si substrates and RuO2/SiO2/Si structures. During plasma deposition, in situ Optical Emission Spectroscopy (OES) measurements clearly show a correlation between the evolution of characteristic atomic emission line intensities and the thin film composition determined by simultaneous Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA). As a result, the cathode surface state can be monitored by OES to ensure a good compositional transferability from the target to the film and reproducibility of thin film properties for given values of deposition parameters. Electrical properties and crystallization have been optimized with a 90 nm PZT thin film grown on RuO2 electrodes. These PZT films, annealed with a very modest thermal budget (550°C) are fatigue-free and show very low leakage currents (J=2.10−8 A/cm2 at 1 V). The use of a metallic target allows us to control the oxygen incorporation in the PZT thin film and also, using 18O as a tracer, to study the oxygen vacancy migration which plays a key role in fatigue, leakage current, and electrical degradation/breakdown in PZT thin films.

scholarly journals Effects of Acetylacetone Additions on PZT Thin Film Processing

1994 ◽  
Vol 361 ◽  
Author(s):  
Robert W. Schwartz ◽  
R.A. Assink ◽  
D. Dimos ◽  
M.B. Sinclair ◽  
T.J. Boyle ◽  
...  
Keyword(s):  
Thin Film ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Precursor Solution ◽  
Lead Zirconate ◽  
Pzt Thin Film ◽  
Precursor Structure ◽  
Drying Behavior ◽  
Ceramic Microstructure ◽  
Gel Processing

ABSTRACTSol-gel processing methods are frequently used for the fabrication of lead zirconate titanate (PZT) thin films for many electronic applications. Our standard approach for film fabrication utilizes lead acetate and acetic acid modified metal alkoxides of zirconium and titanium in the preparation of our precursor solutions. This report highlights some of our recent results on the effects of the addition of a second chelating ligand, acetylacetone, to this process. We discuss the changes in film drying behavior, densification and ceramic microstructure which accompany acetylacetone additions to the precursor solution and relate the observed variations in processing behavior to differences in chemical precursor structure induced by the acetylacetone ligand. Improvements in thin film microstructure, ferroelectric and optical properties are observed when acetylacetone is added to the precursor solution.

Effects of Added Mass on Lead-Zirconate-Titanate (PZT) Thin-Film Microactuators in Aqueous Environments

2013 ◽  
Author(s):  
Chuan Luo ◽  
Chen-Wei Yang ◽  
G. Z. Cao ◽  
I. Y. Shen
Keyword(s):  
Thin Film ◽  
Lead Zirconate Titanate ◽  
Silicon Substrate ◽  
Laser Doppler Vibrometer ◽  
Lead Zirconate ◽  
Added Mass ◽  
Surrounding Water ◽  
Zirconate Titanate ◽  
Pzt Thin Film ◽  
Aqueous Environments

In this paper, we conduct experimental and theoretical studies of a lead-zirconate-titanate (PZT) thin-film microactuator probe submerged in water. The microactuator consists of a base silicon diaphragm, a layer of bottom electrode, a layer of lead-zirconate-titanate (PZT) thin film, and a layer of top electrode. The diaphragm is anchored on a silicon substrate by etching the silicon substrate from the back to form a cavity under the diaphragm. The diaphragm along with part of its anchor is then diced off from the silicon substrate to form a PZT probe and subsequently packaged with parylene. The probe tip has dimensions of 1 mm × 1 mm × 0.4 mm, while the diaphragm has dimensions of 800 μm × 800 μm × 2 μm. In the experimental study, frequency response functions of actuator displacement are measured via a laser Doppler vibrometer and a spectrum analyzer. The measurements show that the first natural frequency of the microactuator reduces from 80 kHz in air to 20 kHz when the microactuator is submerged in water. A literature search indicates that the surrounding water induces significant added mass to the microactuator. Estimation of the added mass based on theories in fluid mechanics successfully reconcile the predicted frequency to the vicinity of 20 kHz confirming the effects of added mass.

scholarly journals Fabrication and Characterization of PZT Fibered-Epitaxial Thin Film on Si for Piezoelectric Micromachined Ultrasound Transducer

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 455 ◽  
Author(s):  
Pham Ngoc Thao ◽  
Shinya Yoshida ◽  
Shuji Tanaka
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Signal To Noise Ratio ◽  
Lead Zirconate ◽  
Ultrasound Transducer ◽  
High Signal ◽  
Epitaxial Thin Film ◽  
Epitaxial Relationship ◽  
Polycrystalline Thin Films

This paper presents a fibered-epitaxial lead zirconate titanate (PZT) thin film with intermediate features between the monocrystalline and polycrystalline thin films for piezoelectric micromachined ultrasound transducer (pMUT). The grain boundaries confirmed by scanning electron microscopy, but it still maintained the in-plane epitaxial relationship found by X-ray diffraction analyses. The dielectric constant (εr33 = 500) was relatively high compared to those of the monocrystalline thin films, but was lower than those of conventional polycrystalline thin films near the morphotropic phase boundary composition. The fundamental characterizations were evaluated through the operation tests of the prototyped pMUT with the fibered-epitaxial thin film. As a result, its piezoelectric coefficient without poling treatment was estimated to be e31,f = −10–−11 C/m2, and thus reasonably high compared to polycrystalline thin films. An appropriate poling treatment increased e31,f and decreased εr33. In addition, this unique film was demonstrated to be mechanically tougher than the monocrystalline thin film. It has the potential ability to become a well-balanced piezoelectric film with both high signal-to-noise ratio and mechanical toughness for pMUT.

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