A complete analysis of the morphology, crystallographic orientation, and resulting electrical properties of Pb(Zr0.53,Ti0.47) Pb(Nb1/3, Zn2/3)O3 (PZT-PZN) thin films, as well as the electrical behavior when integrated in a cantilever for energy harvesting applications, is presented. The PZT-PZN films were deposited using sol-gel methods. We report that using 20% excess Pb, a nucleation layer of PbTiO3 (PT), and a fast ramp rate provides large grains, as well as denser films. The PZT-PZN is deposited on a stack of TiO2/PECVD SiO2/Si3N4/thermal SiO2/Poly-Si/Si. This stack is designed to allow wet-etching the poly-Si layer to release the cantilever structures. It was also found that the introduction of the poly-Si layer results in larger grains in the PZT-PZN film. PZT-PZN films with a dielectric constant of 3200 and maximum polarization of 30?μC/cm2 were obtained. The fabricated cantilever devices produced ~300–400?mV peak-to-peak depending on the cantilever design. Experimental results are compared with simulations. 1. Introduction The ability to retrofit systems with power consuming electronics without having to consider issues associated with providing an independent power source offers a significant advantage for devices in hard to reach locations [1]. In the past few years there has been an increase in research on small wireless electronic devices [1–3]. Mechanical vibrations have received attention as a potential source of power for sensors and wireless electronics in a wide variety of applications [4]. To accomplish this, improving the piezoelectric material used in the cantilever is of paramount importance [5]. Piezoelectric materials are widely used for various devices, including multilayer capacitors, sensors, and actuators [2, 3, 6]. By the 1950s, the ferroelectric solid solution Pb(Zr1?x Tix)O3 (PZT) was found to have exceptionally high dielectric and piezoelectric properties for compositions close to the morphotrophic phase boundary (MPB) [7, 8]. Research to improve the PZT properties, from the material and electrical standpoint, has been mainly accomplished by doping conventional PZT with different elements to “relax” the material [5, 9]. Previous investigations on the dielectric and electrical properties of many ceramic systems, such as barium titanate (BT), lead zirconate titanate (PZT), lead magnesium niobate (PMN), lead titanate (PT), PMN-PT, PZT-BT, and PMN-PZT have demonstrated the importance of the subject [10–13]. Recently, there has been a great deal of interest in the lead zirconate titanate-lead zinc niobate
References
[1]
S. P. Beeby, M. J. Tudor, and N. M. White, “Energy harvesting vibration sources for microsystems applications,” Measurement Science and Technology, vol. 17, no. 12, article R01, pp. R175–R195, 2006.
[2]
S. Roundy, P. K. Wright, and J. Rabaey, “A study of low level vibrations as a power source for wireless sensor nodes,” Computer Communications, vol. 26, no. 11, pp. 1131–1144, 2003.
[3]
S. Roundy and P. K. Wright, “A piezoelectric vibration based generator for wireless electronics,” Smart Materials and Structures, vol. 13, no. 5, pp. 1131–1142, 2004.
[4]
A. Hajati and S.-G. Kim, “Ultra-wide bandwidth piezoelectric energy harvesting,” Applied Physics Letters, vol. 99, no. 8, Article ID 083105, 2011.
[5]
R. Yimnirun, N. Triamnak, M. Unruan, A. Ngamjarurojana, Y. Laosiritaworn, and S. Ananta, “Ferroelectric properties of Pb(Zr1/2Ti1/2)O3–Pb(Zn1/3Nb2/3)O3 ceramics under compressive stress,” Current Applied Physics, vol. 9, no. 1, pp. 249–252, 2009.
[6]
N. M. White and J. D. Turner, “Thick-film sensors: past, present and future,” Measurement Science and Technology, vol. 8, no. 1, pp. 1–20, 1997.
[7]
A. J. Bell, “Factors influencing the piezoelectric behaviour of PZT and other "morphotropic phase boundary" ferroelectrics,” Journal of Materials Science, vol. 41, no. 1, pp. 13–25, 2006.
[8]
B. Jaffe, W. R. Cook, and H. Jaffe, Piezoelectric Ceramics, Academic Press, 1971.
[9]
E. Fuentes-Fernandez, W. Debray-Mechtaly, M. A. Quevedo-Lopez et al., “Fabrication and characterization of Pb(Zr0.53,Ti0.47)O3–Pb(Nb1/3,Zn2/3)O3 thin films on cantilever stacks,” Journal of Electronic Materials, vol. 40, no. 1, pp. 85–91, 2011.
[10]
Q. M. Zhang, J. Zhao, K. Uchino, and J. Zheng, “Change of the weak-field properties of Pb(ZrTi)O3 piezoceramics with compressive uniaxial stresses and its links to the effect of dopants on the stability of the polarizations in the materials,” Journal of Materials Research, vol. 12, no. 1, pp. 226–234, 1997.
[11]
R. Yimnirun, S. Ananta, A. Ngamjarurojana, and S. Wongsaenmai, “Effects of uniaxial stress on dielectric properties of ferroelectric ceramics,” Current Applied Physics, vol. 6, no. 3, pp. 520–524, 2006.
[12]
G. Yang, S. F. Liu, W. Ren, and B. K. Mukherjee, “Uniaxial stress dependence of the piezoelectric properties of lead zirconate titanate ceramics,” in Symposium on Smart Structures and Materials, vol. 3992 of Proceedings of the SPIE, pp. 103–113, June, 2000.
[13]
R. Yimnirun, “Contributions of domain-related phenomena on dielectric constant of lead-based ferroelectric ceramics under uniaxial compressive pre-stress,” International Journal of Modern Physics B, vol. 20, no. 23, pp. 3409–3417, 2006.
[14]
N. Vittayakorn, G. Rujijanagul, T. Tunkasiri, X. Tan, and D. P. Cann, “Perovskite phase formation and ferroelectric properties of the lead nickel niobate-lead zinc niobate-lead zirconate titanate ternary system,” Journal of Materials Research, vol. 18, no. 12, pp. 2882–2889, 2003.
[15]
H. Fan and H.-E. Kim, “Perovskite stabilization and electromechanical properties of polycrystalline lead zinc niobate-lead zirconate titanate,” Journal of Applied Physics, vol. 91, no. 1, pp. 317–322, 2002.
[16]
N. Vittayakorn, G. Rujijanagul, X. Tan, H. He, M. A. Marquardt, and D. P. Cann, “Dielectric properties and morphotropic phase boundaries in the xPb(Zn1/3Nb2/3)O3 Pb(Zr0.5Ti0.5)O3 pseudo-binary system,” Journal of Electroceramics, vol. 16, no. 2, pp. 141–149, 2006.
[17]
T. Schneller and R. Waser, “Chemical modifications of Pb(Zr0.3,Ti0.7)O3 precursor solutions and their influence on the morphological and electrical properties of the resulting thin films,” Journal of Sol-Gel Science and Technology, vol. 42, no. 3, pp. 337–352, 2007.
[18]
H. N. Al-Shareef, K. R. Bellur, O. Auciello, X. Chen, and A. I. Kingon, “Effect of composition and annealing conditions on the electrical properties of Pb(ZrxTi1-x)O3 thin films deposited by the sol-gel process,” Thin Solid Films, vol. 252, no. 1, pp. 38–43, 1994.
[19]
E. Fuentes-Fernandez, L. Baldenegro-Perez, M. Quevedo-Lopez et al., “Optimization of Pb(Zr0.53,Ti0.47)O3 films for micropower generation using integrated cantilevers,” Solid-State Electronics, vol. 63, no. 1, pp. 89–93, 2011.
[20]
L. A. Baldenegro-Perez, W. Debray-Mechtaly, E. Fuentes-Fernandez et al., “Study on the microstructure and electrical properties of Pb(Zr0.53, Ti0.47)O3 thin-films,” Materials Science Forum, vol. 644, pp. 97–100, 2010.
[21]
H. N. Al-Shareef, D. Dimos, M. V. Raymond, R. W. Schwartz, and C. H. Mueller, “Tunability and calculation of the dielectric constant of capacitor structures with interdigital electrodes,” Journal of Electroceramics, vol. 1, no. 2, pp. 145–153, 1997.
[22]
G. W. Farnell, I. A. Cermak, P. Silvester, and S. K. Wong, “Capacitance and field distributions for interdigital surface-wave transducers,” IEEE Transactions on Sonics and Ultrasonics, vol. 17, no. 3, pp. 188–195, 1970.
[23]
G. Arlt, D. Hennings, and G. De With, “Dielectric properties of fine-grained barium titanate ceramics,” Journal of Applied Physics, vol. 58, no. 4, pp. 1619–1625, 1985.
[24]
G. Yi, Z. Wu, and M. Sayer, “Preparation of Pb(Zr,Ti)O3 thin films by sol gel processing: electrical, optical, and electro-optic properties,” Journal of Applied Physics, vol. 64, no. 5, pp. 2717–2724, 1988.
[25]
S. Watanabe, T. Fujiu, and T. Fujii, “Effect of poling on piezoelectric properties of lead zirconate titanate thin films formed by sputtering,” Applied Physics Letters, vol. 66, pp. 1481–1483, 1995.
[26]
Q.-M. Wang, X.-H. Du, B. Xu, and L. Eric Cross, “Electromechanical coupling and output efficiency of piezoelectric bending actuators,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 46, no. 3, pp. 638–646, 1999.