Abstract
This paper demonstrates the substrate dependency of the c-axis zinc oxide growth in radio-frequency sputtering system. Different deposition conditions were designed to study the influences of Si, SiO2/Si, Au/Ti/Si, and Au/Ti/SiO2/Si substrates on the piezoelectric and crystalline qualities of the ZnO thin films. Experimental results showed that the multilayer of Au/Ti/SiO2/Si-coated silicon substrate provided a surface that facilitated the growth of ZnO thin film with the most preferred crystalline orientation. The 1.5 μm-thick thermally grown amorphous silicon dioxide layer effectively masked the crystalline surface of the silicon substrate, thus allowing the depositions of high-quality 20 nm-thick titanium adhesion layer followed by 150 nm-thick of gold thin film. The gold-coated surface allowed deposition of highly columnar ZnO polycrystalline structures. It was also demonstrated that by lowering the deposition rate at the start of sputtering by lowering RF power to less than one-third of the targeted RF power, a fine ZnO seed layer could be created for subsequent higher-rate deposition. This two-step deposition method resulted in substantially enhanced ZnO film quality compared to single-step approach. The influence of stress relaxation by annealing was also investigated and was found to be effective in releasing most of the residual stress in this layered structure.
Similar content being viewed by others
References
L. Yan, W. Pang, E.S. Kim, W.C. Tang, IEEE Electron. Dev. Lett. 27(4), 246 (2006)
J. Molarius, J. Kaitila, T. Pensala, M. Ylilammi, J. Mater. Sci: Mater. Electron. 14, 431 (2003)
W.J. Jeong, G.C. Park, Solar Energy Mater. Solar Cells 65, 37 (2001)
K.B. Sundaram, A. Khan, Thin Sol. Films 295, 87 (1997)
Y. Yoshino, T. Makino, Y. Katayama, T. Hata, Vacuum 59, 538 (2000)
R. Ondo-Ndong, G. Ferblantier, F. Pascal-Delannoy, A. Boyer, A. Foucaran, Microelectr. J. 34, 1087 (2003)
S.H. Park, B.C. Seo, G. Yoon, H.D. Park, J. Vac. Sci. Technol. A 18, 2432 (2000)
S.Y. Chu, W. Water, J.T. Liaw, J. Eur. Ceram. Soc. 23, 1593 (2003)
J. Golebiowski, J. Mater. Sci. 34, 4661 (1999)
Y. Yoshino, Y. Ushimi, H. Yamada, M. Takeuchi, Second International Symposium on Acoustic Wave Devices for Future Mobile Communication Systems. 163 (2004)
A. Cimpoiasuy, N.M. van der Pers, Th.H. de Keyser, A. Venema, M.J. Vellekoop, Smart Mater. Struct. 5, 744 (1996)
B.D. Cullity, in Elements of X-Ray Diffraction, (Addison-Wesley, Massachusetts, 1978), Ch. 16
T. Xu, G. Wu, G. Zhang, Y. hao, Sensors Struct. A 104, 61 (2003)
J.G.E. Gardeniers, Z.M. Rittersma, G.J. Burger, J. Appl. phys. 83, 7844 (1998)
Acknowledgments
The authors acknowledge the continuous support by Jake Hes for the RF sputtering system. Dr. Wen-An Chiou who assisted with the XRD operation and data collection, and Dr. Daniel Mumm, Dr. John Porter, and W.M. Wong for SEM imaging. Funding for this research is partially supported by the California Institute for Telecommunications and Information Technology (Calit2) Emulex Graduate Fellowship.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hsu, YH., Lin, J. & Tang, W.C. RF sputtered piezoelectric zinc oxide thin film for transducer applications. J Mater Sci: Mater Electron 19, 653–661 (2008). https://doi.org/10.1007/s10854-007-9415-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10854-007-9415-1