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.

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.

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.

Electrical and Optical Properties of Sol-Gel Processed Pb(Zr,Ti)o3 Films

1992 ◽  
Vol 271 ◽  
Author(s):  
S. D. Ramamurthi ◽  
S. L. Swartz ◽  
K. R. Marken ◽  
J. R. Busch ◽  
V. E. Wood Battelle
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Optical Characterization ◽  
Solvent System ◽  
Processing Parameters ◽  
Lead Zirconate ◽  
Electrical And Optical Properties ◽  
Annealing Conditions ◽  
Electro Optic ◽  
Pzt Films

ABSTRACTLead-zirconate-titanate, Pb(Zr0.53Ti0.47)O3, films were produced by the sol-gel method from alkoxide and acetate precursors in a 2-methoxyethanol solvent system. The PZT films were deposited on platinized silicon and single-crystal SrTiO3 substrates for electrical and optical characterization, respectively. The processing parameters, especially excess PbO content and annealing conditions, were shown to have a significant effects on the properties of PZT films. Epitaxial PZT films deposited on SrTiO3 waveguided over 10 mm distances with propagation losses as low as 5.9 dB/cm at 783 nm and a linear electro-optic effect was also demonstrated.

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.

Optimization of Thermal Processing and Chemistry in the Fabrication of a PZT Based Mems Power Generator

2002 ◽  
Vol 718 ◽  
Author(s):  
B.W. Olson ◽  
J.L. Skinner ◽  
C.D. Richards ◽  
R.F. Richards ◽  
D.F. Bahr
Keyword(s):  
Lead Zirconate Titanate ◽  
Thermal Processing ◽  
Fatigue Behavior ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Structure Property ◽  
Power Generator ◽  
Structure Property Relationships ◽  
Pzt Film

AbstractThin films of lead zirconate titanate (PZT) are currently being used in a novel MEMS device to generate power. A piezoelectric stack consisting of platinum/PZT/gold is deposited by sputtering, spin coating, and subsequent heat treatments onto a thin silicon membrane, which is cyclically polarized by a flexing motion. The membrane must withstand strains between 0.1% and 0.5% for several billion cycles to provide a useful device. This study has examined the processing-structure-property relationships in developing the PZT film for use in this device. In the sol-gel deposition of PZT, pyrolysis and crystallization temperatures have been shown to alter both microstructure and properties of the piezoelectric film. The chemistry of the PZT film has also been tailored to increase piezoelectric output for this device. Ferroelectric properties are compared to the piezoelectric outputs, and fatigue behavior is measured on bulk silicon and on membranes.

Sol-Gel Process and Properties of Textured Pb(Zr, Ti)O3 Films on Silicon Wafers

2007 ◽  
Vol 280-283 ◽  
pp. 239-242 ◽  
Author(s):  
Wen Gong ◽  
Xiang Cheng Chu ◽  
Jing Feng Li ◽  
Zhi Lun Gui ◽  
Long Tu Li
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Silicon Wafers ◽  
Seeding Layer ◽  
Pzt Thin Films ◽  
Pzt Film ◽  
Sol Gel Process ◽  
Pzt Films

Lead zirconate titanate (PZT) thin films with a composition near the morphotropic phase boundary were deposited on silicon wafers by using a modified sol-gel method. Introducing a seeding layer between the interface of PZT film and platinum electrode controlled the texture of PZT films. The lead oxide seeding layer results in highly (001)-textured PZT film, while the titanium dioxide seeding layer results in (111)-textured one. SEM and XRD were used to characterize the PZT thin films. The ferroelectric and piezoelectric properties of the PZT films were evaluated and discussed in association with different preferential orientations.

Rapid thermal processing of lead zirconate titanate thin films on Pt–GaAs substrates based on a novel 1,1,1-tris(hydroxymethyl)ethane sol-gel route

1999 ◽  
Vol 14 (2) ◽  
pp. 494-499 ◽  
Author(s):  
S. Arscott ◽  
R. E. Miles ◽  
J. D. Kennedy ◽  
S. J. Milne
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Thermal Processing ◽  
Sol Gel ◽  
Rapid Thermal Processing ◽  
Low Frequency ◽  
Lead Zirconate ◽  
Si Substrates ◽  
Pzt Film ◽  
Gaas Substrates

0.53Ti0.47)O3 have been prepared on platinized GaAs (Pt–GaAs) substrates using a new 1,1,1-tris(hydroxymethyl)ethane (THOME) based sol-gel technique. Rapid thermal processing (RTP) techniques were used to decompose the sol-gel layer to PZT in an effort to avoid problems of GayAs outdiffusion into the PZT. A crystalline PZT film was produced by firing the sol-gel coatings at 600 or 650 ° for a dwell time of 1 s using RTP. A single deposition of the precursor sol resulted in a 0.4 μm thick PZT film. X-ray diffraction measurements revealed that the films possessed a high degree of (111) preferred orientation. Measured average values of remanent polarization (Pr ) and coercive field (Ec) for the film annealed at 650 ° for 1 s were 24 μC/cm2 and 32 kV/cm, respectively, together with a low frequency dielectric constant and loss tangent at 1 kHz of 950 and 0.02. These values are comparable to those obtainable on platinized silicon (Pt–Si) substrates using conventional sol-gel methods, and are an improvement on PZT thin films prepared on platinized GaAs using an earlier sol-gel route based on 1,3-propanediol.

Characteristics of Metal/PZT/p—Si MIS Capacitors

1990 ◽  
Vol 200 ◽  
Author(s):  
T.S. Kalkur ◽  
George Argos ◽  
Lee Kammerdiner
Keyword(s):  
Lead Zirconate Titanate ◽  
High Frequency ◽  
Lead Zirconate ◽  
Effective Dielectric Constant ◽  
Annealing Conditions ◽  
Pzt Film ◽  
Rapid Thermal Annealer ◽  
Sputter Deposited ◽  
Mis Capacitors

ABSTRACTLead Zirconate Titanate (PZT) thin films have been sputter deposited on p–Si. The patterned PZT films were annealed in a furnace as well as in a rapid thermal annealer. The high frequency characterization of metal–PZT– p– Si capacitors show good Capacitance–Voltage characteristics. The effective dielectric constant of PZT on Si was found to be very low and depends on the thickness of the PZT film and the annealing conditions. The high frequency C–V shows hysteresis which is due to the injection of charges across the interface.

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