THE EFFECTS OFTI/PTBOTTOM ELECTRODE ON CRYSTALLOGRAPHIC AND SURFACE CHARACTERISTICS OFPZTTHICK FILMS

2012 ◽  
Vol 05 ◽  
pp. 801-809
Author(s):  
ALI KOOCHEKZADEH ◽  
ESKANDAR KESHAVARZ ALAMDARI ◽  
ABDOLGHAFAR BARZEGAR
Keyword(s):  
Lead Zirconate Titanate ◽  
Silicon Substrate ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Surface Characteristics ◽  
Lead Zirconate ◽  
Preferred Orientation ◽  
Mems Devices ◽  
Platinum Surface ◽  
Pzt Films

The ceramic lead zirconate titanate ( PZT ) films near the morphotropic phase boundary are successfully integrated into MEMS devices, especially for applications in microsensors and actuators. The ferro/piezo electric properties of PZT thick films are widely dependent on its surface quality and crystallographic orientation growth. This paper indicates the influences of platinum bottom electrode on the surface and crystallographic properties of PZT . Ti (10 nm ) and Pt (100 nm ) thin films have been deposited on silicon substrate by thermal evaporation and electron beam respectively without vacuum breaking. After annealing treatment, the Pt film exhibited (111) preferred orientation. Finally one micron thick PZT (54/46) film was deposited by a RF magnetron sputtering at room temperature in pure Argon followed by a conventional post annealing treatment on silicon substrate. The XRD measurements have shown the provskite structure of PZT films with (100) preferred orientation at annealing temperatures above 600°C and (111) preferred orientation above 650°c. The SEM results demonstrate that whatever the annealing temperature is increased, recrystallization grains and black holes on Pt surface occurs and cause morphological change of PZT surface. The AFM test shows the strong RMS roughness of platinum surface after annealing temperature at 650°C.

Thermal Effects of Platinum Bottom Electrodes on PZT Sputtered Thin Films Used in MEMS Devices

2010 ◽  
Vol 437 ◽  
pp. 598-602 ◽  
Author(s):  
Ali Koochekzadeh ◽  
Eskandar Keshavarz Alamdari ◽  
Abod Al Ghafar Barzegar ◽  
Ali A. Salardini
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Silicon Substrate ◽  
Annealing Temperature ◽  
Bottom Electrode ◽  
Film Surface ◽  
Annealing Treatment ◽  
Preferred Orientation ◽  
Mems Devices ◽  
Nano Size

For an optimum performance of MEMS devices such as microactuators and microsensors based on piezoelectric thin films a Si/Ti/Pt bottom electrode is widely used. This study shows temperature dependence of surface morphology of both platinum bottom electrode and piezoelectric lead titanate zirconate (PZT) thin films. Ti (10 nm) and Pt (100 nm) thin films were deposited on silicon substrate by thermal evaporation and electron beam, respectively, without vacuum breaking. After annealing treatment, the Pt film exhibited (111) preferred orientation. Finally a 0.8 micron thick PZT (54/46) films were deposited by r.f. magnetron sputtering at room temperature in pure Ar followed by a conventional post annealing treatment on silicon substrate. The XRD measurements have shown the perovskite structure of PZT films with (100) preferred orientation growth. The roughness of platinum film measured by AFM test showed the continuous smoothness of platinum surface for different annealing temperatures. The SEM test results demonstrated that irrespective of the annealing temperature increases, recrystallization of platinum and nano-size holes on Pt surface occurred. The latter caused the acceleration of out-diffusion titanium atoms through Pt layer and reach to the other side of surface. The surface state of Pt thin film is very important as it could strongly influence the PZT surface morphology so the existence of bubbles and depression on PZT surface are increased with both recrystallization of Pt grains and nano-size holes on Pt film surface when the annealing temperature increased.

Intermetallic Formation in PZT for MEMS Structures

2012 ◽  
Vol 1427 ◽  
Author(s):  
Kanu priya Sharma ◽  
Thomas Oseroff ◽  
Leda Lunardi
Keyword(s):  
Electron Microscopy ◽  
Lead Zirconate Titanate ◽  
Surface Film ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Mems Devices ◽  
Aging Effects ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Pzt Films

ABSTRACTCrack free lead zirconate titanate (PZT) films for piezoelectric based MEMS devices have been prepared by a multiple coating sol gel process on platinized silicon (100) substrates. Rapid thermal annealing and Conventional furnace annealing were used for densification and crystallization of the amorphous PZT films. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Atomic force microscopy (AFM) were used to observe surface film morphology and grain growth. The phase content of the films was analyzed using X-ray diffraction. The role of intermetallics formed during the heat treatment in the growth of different orientations has also been observed. Film aging critical for device performance has been observed and methods to revert aging effects have been examined and discussed.

Effect of Processing Conditions on the Piezoelectric Properties of Sol-gel Derived Pb(Zr,Ti)O3 Films for Micromechanical Applications

2005 ◽  
Vol 20 (6) ◽  
pp. 1428-1435 ◽  
Author(s):  
J. Pérez ◽  
P.M. Vilarinho ◽  
A.L. Kholkin ◽  
J. Manuel Herrero ◽  
C. Zaldo
Keyword(s):  
Lead Zirconate Titanate ◽  
Annealing Temperature ◽  
Piezoelectric Properties ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Piezoelectric Response ◽  
Preparation Conditions ◽  
Sol Gel Process ◽  
Pzt Films ◽  
Interface Effects

Lead zirconate titanate (PZT) films of composition close to the morphotropic phase boundary were deposited onto standard Si/SiO2/Ti/Pt substrates using a modified sol-gel process. The preparation conditions were optimized to obtain high-quality films at sufficiently low temperature (Ta - 500 °C). The dielectric, ferroelectric, and piezoelectric properties of the films were then measured as a function of the annealing temperature and the number of distillations to evaluate their suitability for micromechanical applications. The maximum values of the longitudinal charge and voltage piezoelectric coefficients were d33 ∼ 65 pm/V and g33 ∼ 4 × 10−3 Vm/N, respectively. The results indicate that the piezoelectric properties improved and became saturated with increasing number of distillations and are almost independent on Ta. Only moderate decrease of the piezoelectric response with frequency suggests that the investigated PZT films can be used in high-frequency piezoelectric applications. The results are discussed in terms of the microstructure and interface effects on the piezoelectric deformation in ferroelectric thin films.

Pt/TiO2 Growth Templates for Enhanced PZT films and MEMS Devices

2011 ◽  
Vol 1299 ◽  
Author(s):  
Daniel M. Potrepka ◽  
Glen R. Fox ◽  
Luz M. Sanchez ◽  
Ronald G. Polcawich
Keyword(s):  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Crystal Habit ◽  
Piezoelectric Response ◽  
Structural Quality ◽  
Mems Devices ◽  
Sputtering Deposition ◽  
Pzt Films ◽  
The Relationship ◽  
Si Wafer

ABSTRACTThe crystallographic texture of lead zirconate titanate (PZT) thin films strongly influences the piezoelectric properties used in MEMS applications. For PZT films poled to saturation, the piezoelectric response is sequentially greater for random, {111}, and {001} texture. Textured growth can be achieved by relying on crystal growth habit and can also be initiated by the use of a seed layer that provides a heteroepitaxial template. Template choice and the process used to form it determine the structural quality and ultimately influence performance and reliability of MEMS PZT devices such as switches, filters, and actuators. This study focuses on how {111}-textured PZT is generated by a combination of crystal habit and templating mechanisms that occur in the PZT/bottom-electrode stack. The sequence begins with {0001}-textured Ti deposited on thermally grown SiO2 on a Si wafer. The Ti is converted to {100}-textured TiO2 (rutile) through thermal oxidation. Then {111}-textured Pt can be grown to act as a template for {111}-textured PZT. The Ti and Pt are deposited by DC magnetron sputtering. The TiO2 and Pt film textures and structure were optimized by variation of sputtering deposition times, temperatures and power levels, and post-deposition anneal conditions. The relationship between Ti, TiO2, and Pt texture and their impact on PZT growth will be presented.

Ion Beam Sputter Deposition Of Ferroelectric Oxide Thin Films

1991 ◽  
Vol 223 ◽  
Author(s):  
Thomas M. Graettinger ◽  
O. Auciello ◽  
M. S. Ameen ◽  
H. N. Al-Shareef ◽  
K. Gifford ◽  
...  
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Growth Parameters ◽  
Ion Beam ◽  
Lead Zirconate ◽  
Electro Optic ◽  
Integrated Optical ◽  
Pzt Films ◽  
Ion Beam Sputter Deposition ◽  
Ferroelectric Oxide

ABSTRACTFerroelectric oxide films have been studied for their potential application as integrated optical materials and nonvolatile memories. Electro-optic properties of potassium niobate (KNbO3) thin films have been measured and the results correlated to the microstructures observed. The growth parameters necessary to obtain single phase perovskite lead zirconate titanate (PZT) thin films are discussed. Hysteresis and fatigue measurements of the PZT films were performed to determine their characteristics for potential memory devices.

Sol-Gel Derived PZT Thick Films with Nano-Sized Microstructure

2002 ◽  
Vol 748 ◽  
Author(s):  
C. L. Zhao ◽  
Z. H. Wang ◽  
W. Zhu ◽  
O. K. Tan ◽  
H. H. Hng
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Thick Films ◽  
Sol Gel ◽  
Essential Element ◽  
Processing Parameters ◽  
Lead Zirconate ◽  
Piezoelectric Response ◽  
Coupling Coefficients ◽  
Pzt Films

ABSTRACTLead zirconate titanate (PZT) films are promising for acoustic micro-devices applications because of their extremely high electromechanical coupling coefficients and excellent piezoelectric response. Thicker PZT films are crucial for these acoustic applications. A hybrid sol-gel technology has been developed as a new approach to realize simple and cost-effective fabrication of high quality PZT thick films. In this paper, PZT53/47 thick films with a thickness of 5–50 μm are successfully deposited on Pt-coated silicon wafer by using the hybrid sol-gel technology. The obtained PZT thick films are dense, crack-free, and have a nano-sized microstructure. The processing parameters of this technology have been evaluated. The microstructure of the film has been observed using field-emission scanning electron microscopy and the crystallization process has been monitored by the X-ray diffraction. The thick films thus made are good candidates for fabrication of piezoelectric diaphragm which will be an essential element of microspeaker and microphone arrays.

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.

Microstructure of Compositionally Graded PZT films Grown by Pulsed Laser Deposition

2008 ◽  
Vol 14 (S3) ◽  
pp. 53-56
Author(s):  
S.A.S. Rodrigues ◽  
A. Khodorov ◽  
M. Pereira ◽  
M.J.M. Gomes
Keyword(s):  
Pulsed Laser Deposition ◽  
Lead Zirconate Titanate ◽  
Film Growth ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Lead Zirconate ◽  
Laser Deposition ◽  
Composition Gradient ◽  
Complex Structures ◽  
Pzt Films

Ferroelectric films with a composition gradient have attracted much attention because of their large polarization offset present in the hysteresis loops. Lead Zirconate Titanate (PZT) films were deposited on Pt/TiO2/SiO2/Si substrates by Pulsed Laser Deposition (PLD) technique, using a Nd:YAG laser (Surelite) with a source pulse wavelength of 1064 nm and duration of 5-7 ns delivering an energy of 320 mJ per pulse and a laser fluence energy about 20 J/cm2. The film growth is performed in O2 atmosphere (0,40 mbar) while the substrate is heated at 600°C by a quartz lamp. Starting from ceramic targets based on PZT compositions and containing 5% mol. of excess of PbO to compensate the lead evaporation during heat treatment, three films with different compositions Zr/Ti 55/45, 65/35 and 92/8, and two types of complex structures were produced. These complex structures are in the case of the up-graded structure (UpG), with PZT (92/8) at the bottom, PZT (65/35) on middle and PZT (55/45) on the top, and for down-graded (DoG) one, that order is reversed.

Mist Deposition of Micron-Thick Lead Zirconate Titanate Films

2003 ◽  
Vol 784 ◽  
Author(s):  
Mark D. Losego ◽  
Susan Trolier-McKinstry
Keyword(s):  
Lead Zirconate Titanate ◽  
Chemical Deposition ◽  
Lead Zirconate ◽  
Limiting Factors ◽  
Process Time ◽  
Silicon Substrates ◽  
Zirconate Titanate ◽  
Pzt Films ◽  
Chamber Temperature ◽  
Thick Lead

ABSTRACTA majority of the work published on liquid source misted chemical deposition (LSMCD) has focused on the fabrication of thin ferroelectric films for random access memory (RAM) applications. However, the ability of LSMCD to combine the characteristically good stoichiometry control of a chemical solution deposition process with good film conformality, makes this a desirable technique for other applications, including microactuators and integrated passive components. For these applications, though, LSMCD is limited by its low throughput. This paper describes the feasibility of depositing micron-thick lead zirconate titanate (PZT) films using the LSMCD tool. PZT films of 52/48 composition were deposited on both platinized silicon and platinized alumina substrates. The chamber temperature and the delivery geometry of the LSMCD tool were identified as limiting factors in the rate at which micron-thick samples can be prepared. By switching to a focused nozzle delivery geometry and increasing the chamber temperature from room temperature to 60°C, the total process time for 1 μm thick films can be reduced from 480 min to 90 min. Polarization hysteresis measurements indicated a 75% higher remanent polarization for PZT films deposited on platinized alumina substrates (35 μC/cm2) compared to those deposed on platinized silicon substrates (20 μC/cm2). The polarization loop for the silicon substrate sample was also tilted. These observations are evidence of higher tensile stresses in the PZT films deposited on silicon substrates due to a larger mismatch in the thermal expansion coefficients of the film and the substrate.

Fabrication of Thick, Sol Gel Pzt Films: Applications to Macroscopic Piezoelectric Devices

1994 ◽  
Vol 360 ◽  
Author(s):  
D.A. Barrow ◽  
T.E. Petroff ◽  
M. Sayer
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Low Frequency ◽  
Lead Zirconate ◽  
Resonant Vibrations ◽  
Pzt Film ◽  
Sol Gel Process ◽  
Pzt Films ◽  
High Frequency Resonance ◽  
Piezoelectric Devices

AbstractLead zirconate titanate (PZT) films of up to 60 μm in thickness have been fabricated on a wide variety of substrates using a new sol gel process. The dielectric properties (∈ = 900), ferroelectric (Ec = 16 kV/cm and Pr = 35 μC/cm 2) and piezoelectric properties are comparable to bulk values. The characteristic Curie point of these films is at 420 °C. Piezoelectric actuators have been developed by depositing thick PZT films on both planar and coaxial substrates. Stainless steel cantilevers and optical fibres coated with a PZT film exhibit flexure mode resonant vibrations observable with the naked eye. A low frequency in-line fibre optic modulator has been developed using a PZT coated optical fibre. The high frequency resonance of a 60 μm film on a aluminum substrate has been observed.

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