Integration of PZT on SOI Wafers: Increasing Piezoelectric Film Thickness for Providing a Wide Range of Ultrasonic MEMS Applications

2006 ◽  
Vol 969 ◽  
Author(s):  
Brahim Belgacem ◽  
Florian Calame ◽  
Paul Muralt
Keyword(s):  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Sol Gel ◽  
Equivalent Circuit Model ◽  
Ultrasonic Transducers ◽  
Electromechanical Coupling Coefficient ◽  
Wide Range ◽  
Pzt Films ◽  
Gel Technique ◽  
Quality Factor Q

AbstractPiezoelectric micromachined ultrasonic transducers comprising a 10 μm thick Si device layer and a 1-4 μm thick piezoelectric PZT layer were investigated. The PZT films were deposited by a sol-gel technique. The transverse piezoelectric coefficient was measured as -14.9 C/m2. The electromechanical coupling increased with PZT thickness, as expected. The influence of both the shape and area of the top electrode on the device performance has been investigated. The electromechanical coupling coefficient (k) and quality factor (Q) have been measured in air and were fitted to an equivalent circuit model. The maximal k2 was obtained as 7.8%.

Effect of Additive Glycerol on Piezoelectric Properties of Modified Sol-Gel (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 Ceramics

2020 ◽  
Vol 993 ◽  
pp. 791-798
Author(s):  
Haibibu Aziguli ◽  
Tao Zhang ◽  
Ping Yu
Keyword(s):  
Grain Size ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Environmental Concern ◽  
Sol Gel ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Electromechanical Coupling Coefficient ◽  
Ceramic Powders

Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) ceramics, one of the lead-free pizoelectric materials, were focused due to the environmental concern against lead. A modified BCTZ powder sol-gel fabrication process was experimentally introduced with the addition of glycerol, in order to provide an effective approach to optimize the piezoelectric response of BCTZ ceramics. The results showed that the piezoelectric properties enhanced in terms of the piezoelectric coefficient of d33, 510 pC/N and the electromechanical coupling coefficient of kp, 0.501. The enhancement in electrical properties, such as dielectric, ferroelectric and piezoelectric, could be related to the homogenous microstructure and larger grain size of BCTZ ceramic powders after the introduction of glycerol during the modified sol-gel strategy.

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.

Sb5+ Modified Phase Transition in (Li, Na, K)(Nb1-xSbx)O3 Piezoelectric Ceramics

2016 ◽  
Vol 848 ◽  
pp. 339-343
Author(s):  
Xiao Kun Zhao ◽  
Bo Ping Zhang ◽  
Lei Zhao ◽  
Li Feng Zhu
Keyword(s):  
Phase Transition ◽  
Phase Boundary ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Electromechanical Coupling Coefficient ◽  
Second Phase ◽  
Phase Transition Temperatures ◽  
Two Peaks ◽  
Planar Mode

The modified behavior of the phase transition temperatures (TO-T and/or TC) between orthorhombic (O), tetragonal (T) and cubic (C) that caused by doping Sb5+ in (Li0.052Na0.493K0.455)(Nb1-xSbx)O3 (LNKNSx) ceramics was reported in the present investigation. The results show that differing from the insensitive TO-T to the Sb5+ content, TC splits into two peaks TCI and TCII when doping Sb5+. The decreased TCI by raising x may be ascribed to the Sb-rich grains and the settled TCII round 480 °C resulting from the Sb-lack ones. The enhanced piezoelectric coefficient d33 value of 263 pC/N and planar mode electromechanical coupling coefficient kp value of 42.5% at x=0.052 can be attributed to the polymorphic phase boundary (PPB) behavior with an appropriate ratio between T and O phases without any second phase.

Oxygen Tracer Diffusion in Sol-Gel Derived Pb(Zr,Ti)O3 thin Films

1993 ◽  
Vol 310 ◽  
Author(s):  
John J. Vajo ◽  
L.A. Momoda ◽  
S.B. Wong ◽  
G.S. Kamath
Keyword(s):  
Thin Films ◽  
Oxygen Diffusion ◽  
Sol Gel ◽  
Finite Thickness ◽  
Tracer Diffusion ◽  
Pzt Films ◽  
Gel Technique ◽  
Low Levels ◽  
Secondary Ion ◽  
Oxygen Tracer

AbstractWe have studied oxygen diffusion in thin films of Pb(Zr,Ti)O3 on Pt/Ti/SiO2/Si <100> multilayer substrates using 18O as a tracer. The PZT films were synthesized using the sol-gel technique and crystallized in air at 650° C for 30 minutes. Diffusion experiments were conducted in one atmosphere of 18O2 at tmipertures between 400-600°C, the extent of exchange was monitored using secondary ion mass spectromentry. Exchange profiles were modeled using solutions of the diffusion equation with boundary conditions for a layer with finite thickness. Significant exchange (>60%) of 16O by 18O was measured after treatment under conditions similar to those used for crystallization. At low levels of exchange, oxygen diffusion does not follow a simple Fickian profile and differences exist between nominally identical films. These results suggest that oxygen exchange is sensitive to the film's microstructure.

Preparation of PbZrxTi1−xO3 Films on Si Substrates Using SrTiO3 Buffer Layers

1994 ◽  
Vol 361 ◽  
Author(s):  
Eisuke Tokumitsu ◽  
Kensuke Itani ◽  
Bum-Ki Moon ◽  
Hiroshi Ishiwara
Keyword(s):  
Buffer Layer ◽  
Secondary Ion Mass Spectrometry ◽  
Sol Gel ◽  
Buffer Layers ◽  
Si Substrates ◽  
Pzt Film ◽  
Pzt Films ◽  
Evaporation Technique ◽  
Gel Technique ◽  
Secondary Ion

ABSTRACTWe report the preparation of PbZrxTi1−xO3 (PZT) films on Si substrates with a SrTiO3 (STO) buffer layer. STO buffer layers and PZT films were formed on Si substrates by the electron-beam assisted vacuum evaporation technique and sol-gel technique, respectively. By evaporating a thin (8nm) metal Sr layer prior to the STO deposition, which deoxidizes the SiO2 layer at the Si surface, (100)- and (111)-oriented STO thin films can be grown on Si(100) and (111) substrates, respectively. It is shown that a strongly (100)-oriented PZT film is grown on STO(100)/Si(100), whereas a strongly (111)-oriented PZT film is obtained on STO(111)/Si(111). It is also found that the STO buffer layer remains intact even after the PZT deposition. Secondary ion mass spectrometry (SIMS) analysis showed that the STO barrier layer was effective in preventing diffusion of Pb into the Si substrate.

Wet-Etch Patterning of Lead Zirconate Titanate (PZT) Thick Films for Microelectromechanical Systems (MEMS) Applications

2000 ◽  
Vol 657 ◽  
Author(s):  
L.-P. Wang ◽  
R. Wolf ◽  
Q. Zhou ◽  
S. Trolier-McKinstry ◽  
R. J. Davis
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Microelectromechanical Systems ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Metal Fluoride ◽  
Zirconate Titanate ◽  
Pzt Films ◽  
High Etch Rate ◽  
Wet Etch

ABSTRACTLead zirconate titanate (PZT) films are very attractive for microelectromechanical systems (MEMS) applications because of their high piezoelectric coefficients and good electromechanical coupling. In this work, wet-etch patterning of sol-gel PZT films for MEMS applications, typically with film thicknesses ranging from 2 to 10 microns, was studied. A two- step wet-etch process was developed. In the first step, 10:1 buffered HF is used to remove the majority of the film at room temperature. Then a solution of 2HCl:H2O at 45°C is used to remove metal-fluoride residues remaining from the first step. This enabled successful patterning of PZT films up to 8 microns thick. A high etch rate (0.13μm/min), high selectivity with respect to photoresist, and limited undercutting (2:1 lateral:thickness) were obtained. The processed PZT films have a relative permittivity of 1000, dielectric loss of 1.6%, remanent polarization (Pr) of 24μC/cm2, and coercive field (Ec) of 42.1kV/cm, all similar to those of unpatterned films of the same thickness.

Piezoelectric and Strain Properties of Strontium-Doped BZT-BCT Lead-Free Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1385-1389 ◽  
Author(s):  
Wang Feng Bai ◽  
Wei Li ◽  
Bo Shen ◽  
Ji Wei Zhai
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Free Material

Lead-free piezoelectric ceramics, (Ba0.85-xSrxCa0.15)(Zr0.1Ti0.9)O3 (BSCZT, x=0.01-0.07), were prepared via a solid-state reaction route. The dielectric properties, ferroelectric properties, piezoelectric and strain properties of BSCZT ceramics were studied. The phase structure and microstructure were investigated by X-ray diffraction and scanning electron microscope, respectively. Results showed that dense ceramics with pure perovskite phase were obtained. At room temperature, the samples with x=0.03 exhibited excellent properties with large piezoelectric coefficient d33=534pC/N, planar mode electromechanical coupling coefficient kp=47.7%, thickness mode electromechanical coupling coefficient kt= 42% and high strain levels of 0.34%. In addition, the study of electrical properties suggested that the Curie temperature decreased linearly from 92oc to 73oc with the increasing doping content of strontium in BCZT ceramics. The remnant polarizations, piezoelectric coefficient and strain levels were all increased as the Sr content increased and then decreased with further increased Sr doping level, giving the maximum values at the Sr content of 3mol%. These results indicated that the BSCZT system is a promising lead-free material for applications in the future.

Influence of Sintering Temperature on KNN-BF-LS Piezoelectric Ceramic

2016 ◽  
Vol 859 ◽  
pp. 8-12 ◽  
Author(s):  
Guo Yuan Cheng ◽  
Xing Hua Fu ◽  
Wen Hong Tao ◽  
Yu Zhang ◽  
Wen Xin Ma ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Loss ◽  
Piezoelectric Ceramic ◽  
Electromechanical Coupling ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Electromechanical Coupling Coefficient ◽  
Structure And Properties ◽  
Maximum Value

In this paper, (K0.5Na0.53)0.932Nb0.932O3-0.008BF-0.06LS (abbreviated as KNN-BF-LS) piezoelectric ceramic was prepared by sol-gel method. Structure and properties of ceramics were analyzed.Through analysis of the results, when sintering temperature is 1080°C, ceramic has good perovskite structure. At this temperature, grain size is more uniform, and structure is the most dense. Piezoelectric constant d33, electromechanical coupling coefficient Kp, dielectric constant εr reached the maximum value, respectively, 113pC/N, 0.33, 591. Dielectric loss tanδ reached the minimum 0.11.

scholarly journals Hydrothermally synthesized PZT film grown in highly concentrated KOH solution with large electromechanical coupling coefficient for resonator

2017 ◽  
Vol 4 (12) ◽  
pp. 171363 ◽  
Author(s):  
Guo-Hua Feng ◽  
Kuan-Yi Lee
Keyword(s):  
Hydrothermal Synthesis ◽  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Potassium Hydroxide Solution ◽  
Oxide Semiconductor ◽  
Synthesis Process ◽  
Electromechanical Coupling Coefficient ◽  
Coupling Coefficients ◽  
High Concentration ◽  
Pzt Films

This paper presents a study of lead zirconate titanate (PZT) films hydrothermally grown on a dome-shaped titanium diaphragm. Few articles in the literature address the implementation of hydrothermal PZT films on curved-diaphragm substrates for resonators. In this study, a 50-μm-thick titanium sheet is embossed using balls of designed dimensions to shape a dome-shaped cavity array. Through single-process hydrothermal synthesis, PZT films are grown on both sides of the processed titanium diaphragm with good adhesion and uniformity. The hydrothermal synthesis process involves a high concentration of potassium hydroxide solution and excess amounts of lead acetate and zirconium oxychloride octahydrate. Varied deposition times and temperatures of PZT films are investigated. The grown films are characterized by X-ray diffraction and scanning electron microscopy. The 10-μm-thick PZT dome-shaped resonators with 60- and 20-μm-thick supporting layers are implemented and further tested. Results for both resonators indicate that large electromechanical coupling coefficients and a series resonance of 95 MHz from 14 MHz can be attained. The device is connected to a complementary metal–oxide–semiconductor integrated circuit for analysis of oscillator applications. The oscillator reaches a Q value of 6300 in air. The resonator exhibits a better sensing stability when loaded with water when compared with air.

scholarly journals NOVEL LEAD ZIRCONATE TITANATE COMPOSITE VIA FREEZING TECHNOLOGY FOR HIGH FREQUENCY TRANSDUCER APPLICATIONS

2011 ◽  
Vol 01 (01) ◽  
pp. 85-89 ◽  
Author(s):  
B. P. ZHU ◽  
Q. F. ZHOU ◽  
C. H. HU ◽  
K. K. SHUNG ◽  
E. P. GORZKOWSKI ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Room Temperature ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Lead Zirconate ◽  
Electromechanical Coupling Coefficient ◽  
Single Element ◽  
Central Frequency ◽  
Frequency Transducer ◽  
High Frequency Transducer

Novel PZT-5A ceramic-polymer composite was prepared via freezing technology. This composite exhibited good dielectric and ferroelectric behaviors. At 1 kHz, the dielectric constant and the dielectric loss were 546 and 0.046, respectively, while the remnant polarization was 13.0 μC/cm2 at room temperature. The electromechanical coupling coefficient (kt) of PZT-5A composite was measured to be 0.54, which is similar to that of PZT piezoelectric ceramic. The piezoelectric coefficient (d33) of PZT-5A composite was determined to be ~250 pC/N. Using this composite, a 58 MHz single element transducer with the bandwidth of 70% at –6dB was built, and the insertion loss was tested to be –29dB around the central frequency.

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