Development of Aluminum Nitride/Platinum Stack Structures for an Enhanced Piezoelectric Response

2006 ◽  
Vol 955 ◽  
Author(s):  
Adam Kabulski ◽  
John Harman ◽  
Parviz Famouri ◽  
Dimitris Korakakis

ABSTRACTAluminum nitride (AlN) films are being investigated for piezoelectric and high temperature applications, but the piezoelectric response is still much lower than that of more common piezoelectric materials such as lead zirconate titanate or zinc oxide. A method of maximizing the piezoelectric response of aluminum nitride has been explored by depositing stack structures composed of aluminum nitride and platinum. These stack structures were created by depositing a thin, ∼50nm, metal layer in between thicker, ∼150-350nm, layers of the piezoelectric film. Platinum was chosen as the metal interlayer due to the tendency of AlN to become highly c-oriented when deposited on Pt. An electric field was applied across the structure and displacements were measured using a Laser Doppler Vibrometer. A maximum piezoelectric coefficient d33 was found to be over two times larger than the theoretical value for AlN (3.9pm/V). However, some of the stack structures were found to be conductive when measuring the displacement. I-V measurements as well as Fowler-Nordheim theory and plots were applied to investigate tunneling due to high electric fields in the structures.

2008 ◽  
Vol 1129 ◽  
Author(s):  
A. Kabulski ◽  
V. R. Pagán ◽  
D Korakakis

AbstractAluminum nitride (AlN) films have been explored for sensor and actuator applications, but the resultant piezoelectric coefficient is still too low to make the films more competitive with more commonly used piezoelectric materials such as lead zirconate titanate (PZT). While AlN does have the disadvantage of a lower piezoelectric response, it does have the ability to maintain its piezoelectric properties above 400°C, something that is not possible with other piezoelectric materials. It is desirable to achieve a larger piezoelectric response for AlN in order to facilitate the integration of nitride based devices into existing technologies but conventional methods of improving the response by growing higher quality film only result in slight improvements in the piezoelectric response. A method of improving the d33 piezoelectric coefficient beyond any values found in literature may be possible by exploring methods of improving PZT films.Rare earth doping has been reported to improve the piezoelectric properties of PZT resulting in significant increases in the piezoelectric coefficient. Research has been conducted using rare earth dopants to improve upon the optical properties of AlN, but the impact on piezoelectric effect has never been considered.Thin, 250-1000 nm, AlN:Er films have been reactively sputtered using erbium (Er)/aluminum alloyed targets to explore any improvement in piezoelectric properties of the AlN:Er films as compared to AlN films. AlN films with 0.5 and 1.5% Er concentrations have been found to have piezoelectric coefficients that are larger than comparable ‘Er-free’ AlN films. AlN films with only 0.5% Er quantities were found to increase the d33 coefficient compared to a similar AlN film depending on the thickness of the film. This increase results in d33,f values greater than 7pm/V which is larger than most values found in literature. By increasing the Er content to 1.5%, values of d33,f were found to be as large as 15 pm/V. This enhanced piezoelectric response is still lower than that of PZT, but can be used to create superior actuator devices than that of typical AlN films.


2005 ◽  
Vol 20 (7) ◽  
pp. 1641-1653 ◽  
Author(s):  
Xiaoli Tan ◽  
Hui He ◽  
Jian-Ku Shang

High electric fields were delivered to specimens during imaging in the transmission electron microscopy (TEM) chamber to reveal details of electric field-induced phenomena in ferroelectric oxides. These include the polarization switching in nanometer-sized ferroelectric domains and the grain boundary cavitation in a commercial lead zirconate titanate (PZT) polycrystalline ceramic, the domain wall fracture in a Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal, and the transformation of incommensurate modulations in Pb0.99Nb0.02[(Zr1−xSnx)1−yTiy]0.98O3 (PZST100x/100y/2) polycrystalline ceramics. In the PZT ceramic, a cavitation process was uncovered for the electric field-induced intergranular fracture. In the ferroelectric single crystal, a preexisting crack was observed to deflect and to follow a 90° domain wall, indicating the presence of severe incompatible piezoelectric strains at thedomain wall. In the antiferroelectric PZST ceramics, the electric field-induced antiferroelectric-to-ferroelectric phase transformation was accompanied with the disappearance of incommensurate modulations.


Science ◽  
2019 ◽  
Vol 363 (6432) ◽  
pp. 1206-1210 ◽  
Author(s):  
Wei-Qiang Liao ◽  
Dewei Zhao ◽  
Yuan-Yuan Tang ◽  
Yi Zhang ◽  
Peng-Fei Li ◽  
...  

Piezoelectric materials produce electricity when strained, making them ideal for different types of sensing applications. The most effective piezoelectric materials are ceramic solid solutions in which the piezoelectric effect is optimized at what are termed morphotropic phase boundaries (MPBs). Ceramics are not ideal for a variety of applications owing to some of their mechanical properties. We synthesized piezoelectric materials from a molecular perovskite (TMFM)x(TMCM)1–xCdCl3 solid solution (TMFM, trimethylfluoromethyl ammonium; TMCM, trimethylchloromethyl ammonium, 0 ≤ x ≤ 1), in which the MPB exists between monoclinic and hexagonal phases. We found a composition for which the piezoelectric coefficient d33 is ~1540 picocoulombs per newton, comparable to high-performance piezoelectric ceramics. The material has potential applications for wearable piezoelectric devices.


2001 ◽  
Vol 688 ◽  
Author(s):  
Dong-Joo Kim ◽  
Jon-Paul Maria ◽  
Angus I. Kingon

AbstractThe piezoelectric, dielectric, and ferroelectric properties of highly (111)-textured polycrystalline lead zirconate titanate (PZT) films as a function of Zr/Ti composition have been investigated. The peak in piezoelectric coefficient at the morphotropic phase boundary (MPB) observed in bulk PZT ceramics has not been found in thin film PZTs. Measurement of the piezoelectric response as a function of AC amplitude suggests that non-180° domain wall motion in these films is negligible, indicating that the extrinsic contribution to the room temperature dielectric constant is dominated by only 180° domain wall motion. The semi-empirical phenomenological equation relating the piezoelectric coefficient to measured polarization and permittivity values is demonstrated to give an excellent description of the piezoelectric behavior in these films, assuming bulk electrostrictive coefficients. The small deviation between calculated and measured piezoelectric coefficients as well as the dependence of piezoelectric and polarization behavior on the external dc field, i.e., hysteresis loop, are suggested to be primarily due to backswitching of 180° domains.


2002 ◽  
Vol 748 ◽  
Author(s):  
C. L. Zhao ◽  
Z. H. Wang ◽  
W. Zhu ◽  
O. K. Tan ◽  
H. H. Hng

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.


2014 ◽  
Vol 609-610 ◽  
pp. 1331-1335
Author(s):  
Jun Jie Chen ◽  
Ying Liu ◽  
Jian Qiang Ma ◽  
Ji Cong Deng ◽  
Bao Qing Li ◽  
...  

This paper demonstrates that the deformation of the piezoelectric deformable mirror (DM) is proportional to the transverse piezoelectric coefficient of the lead zirconate titanate (PZT) by the theoretical analysis. The optimal polarization conditions were obtained by experiments to optimize the performance of the DM. After the optimal polarization, the transverse piezoelectric coefficient of the PZT film increases from 350 pm/V to 431 pm/V, which will improve the deformation of the DM.


2021 ◽  
Vol 9 (1) ◽  
pp. 1321-1328
Author(s):  
Abdul Aziz Khan J , Shanmugaraja P , Kannan S

MEMS Energy Harvesting(EH) devices are excepted to grow in the upcoming years, due to the increasing aspects of MEMS EH devices in vast applications. In Recent advancements in energy harvesting (EH) technologies wireless sensor devices play a vital role to extend their lifetime readily available in natural resources. In this paper the design of MEMS Cantilever at low frequency (100Hz) with different piezoelectric materials Gallium Arsenide (GaAs), Lead Zirconate Titanate (PZT-8), Tellurium Dioxide (TeO2), Zinc oxide (ZnO) is simulated and performance with different materials are compared. The results are analyzed with various parameters such as electric potential voltage, von mises stress, displacement. The paper discusses the suitability of the piezoelectric material for MEMS fully cochlear implantable sensor application.


Author(s):  
Ryan Rudy ◽  
Adam J. Cohen ◽  
Jeffrey S. Pulskamp ◽  
Ronald G. Polcawich ◽  
Kenn R. Oldham

Terrestrial and other millimeter-scale autonomous micro-robots face significant challenges in surveying their environment, due to small power budgets and payload capacities. One low-power, low-mass form of obstacle detection is tactile sensing of contact with other surfaces. In this-paper, a tactile sensor inspired by insect antennae is described, based on thin-film lead-zirconate-titanate (PZT) transduction. Thin-film piezoelectric materials permit actuation and sensing mechanisms to be coupled in very small, compact structures, as well as complement previously developed microrobotic leg mechanisms. Key design parameters for the tactile sensor are introduced and analyzed in terms of sweep frequency and range of motion, and signals from sensor impact are predicted. Experimental results with partially-released prototype actuators show respectable agreement with modeled behavior for dynamic motion, though impact detection is hampered by large feedthrough disturbances. Completed sensors range from 2 to 4 mm in length and are approximately 500 μm in width, with a sweep range of nearly 1 mm demonstrated from a 2 mm long prototype.


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