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.

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.

Raman analysis of microcircuits with lead zirconate titanate (PZT) films

1992 ◽  
Vol 50 (2) ◽  
pp. 1688-1689
Author(s):  
D. R. Tallant ◽  
R. W. Schwartz ◽  
B. A. Tuttle ◽  
S. C. Everist ◽  
B. C. Tafoya
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Lead Zirconate Titanate ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Solution Chemistry ◽  
Zirconate Titanate ◽  
Pzt Films ◽  
High Temperature Processing

Certain compositions and structural forms of lead zirconate titanate (PZT) materials have potential applications in microelectronics because of their ferroelectric properties. One such application is in the development of new types of non-volatile memories. PZT films are integrated into microcircuit components using sol-gel deposition techniques. The solution chemistry effects attendant to different sol-gel preparation procedures have been investigated by several researchers.We have used Raman spectroscopy both to characterize the metallo-organic species initially laid down on macroscopic platinum substrates during sol-gel processing and to follow the evolution of Pb-Zr-Ti oxide species through high temperature processing. The high temperature processing removes residual organics and creates Pb-Zr-Ti oxide structures that have ferroelectric properties. Low temperature pyrochlore structures, which are not ferroelectric, can be distinguished by Raman spectroscopy from tetragonal and pseudo-cubic/rhombohedral perovskite structures, which are usefully ferroelectric (Top Figure). In addition Raman spectroscopy has identified lead and titanium oxides that form as intermediates in the high temperature crystallization of ferroelectric PZT structures.

Influence of structure and chemistry on piezoelectric properties of lead zirconate titanate in a microelectromechanical systems power generation application

2003 ◽  
Vol 18 (9) ◽  
pp. 2079-2086 ◽  
Author(s):  
L. M. R. Eakins ◽  
B. W. Olson ◽  
C. D. Richards ◽  
R. F. Richards ◽  
D. F. Bahr
Keyword(s):  
Crystal Structure ◽  
Lead Zirconate Titanate ◽  
Microelectromechanical Systems ◽  
Lead Zirconate ◽  
Solution Deposition ◽  
Zirconate Titanate ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
Pzt Films ◽  
Pt Films

Lead zirconate titanate (PZT) films between 1 and 3 μm thick were grown using solution deposition techniques to study the effects of crystal structure and orientation on the direct piezoelectric output of these films on platinized Si membranes. By varying the chemistry of the film from Zr-rich to Ti-rich, the {100}/(111) relative intensity increased for films grown on randomly oriented Pt films. The 40:60 PZT had a tetragonal crystal structure and produced greater electrical output at a given strain than the rhombohedral film (Zr:Ti concentrations less than 50:50), while having a similar e31 constant, between 4.8 and 6.3 C/m2. Orientation and voltage output at a given strain were not strongly influenced by thickness in the ranges investigated. Defects in internal PZT/PZT crystallization interfaces were identified and include porosity on the order of tens of nm, with a corresponding depletion in Pb and accumulation of O at these interfaces. The {100} texture of rhombohedral films deposited upon (111) textured Pt films is significantly greater than the {100} texture of tetragonal films, which show both a {100} and {111} orientation on the same Pt film.

Preparation and Application of Lead Zirconate Titanate (PZT) Films Deposited by Hybrid Process: Sol-Gel Method and Laser Ablation

2002 ◽  
Vol 41 (Part 1, No. 11B) ◽  
pp. 6664-6668 ◽  
Author(s):  
Jiunnjye Tsaur ◽  
Zhan Jie Wang ◽  
Lulu Zhang ◽  
Masaaki Ichiki ◽  
Jiang Wen Wan ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Hybrid Process ◽  
Gel Method ◽  
Sol Gel Method ◽  
Zirconate Titanate ◽  
Pzt Films

Orientation control of sol-gel-derived lead zirconate titanate film by addition of polyvinylpyrrolidone

2005 ◽  
Vol 20 (4) ◽  
pp. 882-888 ◽  
Author(s):  
Gun-Tae Park ◽  
Chee-Sung Park ◽  
Jong-Jin Choi ◽  
Hyoun-Ee Kim
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Organic Residues ◽  
Si Substrates ◽  
Pzt Film ◽  
Oriented Film ◽  
Zirconate Titanate ◽  
Nucleation Sites ◽  
Pzt Films

Highly (100)- and (111)-oriented lead zirconate titanate (PZT) films with a thickness of 350 nm were deposited on platinized Si substrates through a single spinning of a PZT sol containing polyvinylpyrrolidone (PVP) as an additive. The crystallographic orientation of the film was strongly influenced by pyrolysis conditions after spin coating. When the spin-coated sol was pyrolyzed at temperatures above 320 °C for relatively long periods of time (>5 min), (111)-oriented film was formed after annealing at 700 °C for 10 min. On the other hand, when the same sol was pyrolyzed at 320 °C for short periods of time (<5 min), the film was strongly oriented to the (100) direction after annealing. Organic residues derived from PVP decomposition acted as nucleation sites for the (100) oriented grains during annealing after the pyrolysis. The effective d33 of the (100)-oriented PZT film (100 pC/N) was much higher than that of the (111)-oriented film (62 pC/N) with the same thickness.

Early Stages of Crystallization of Sol−Gel-Derived Lead Zirconate Titanate Thin Films

2003 ◽  
Vol 15 (5) ◽  
pp. 1147-1155 ◽  
Author(s):  
A. Wu ◽  
P. M. Vilarinho ◽  
I. Reaney ◽  
I. M. Miranda Salvado
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Early Stages ◽  
Zirconate Titanate

scholarly journals Interfacial mechanisms controlling phase formation in sol-gel derived lead zirconate titanate thin films

1994 ◽  
Vol 17 (6) ◽  
pp. 1005-1014 ◽  
Author(s):  
S B Majumder ◽  
V N Kulkarni ◽  
Y N Mohapatra ◽  
D C Agrawal
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Zirconate Titanate

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.

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