Abstract
In order to obtain both high electromigration (EM) reliability and fine-dimensional control in high-frequency surface acoustic wave (SAW) devices, 4-layered Ti/Al-Mo/Ti/Al-Mo electrode films were investigated on 128° Y-X LiNbO3 substrates by sputtering deposition. The results indicated that the 4-layered films had an improved EM reliability compared to conventional Al-0.5wt.%Cu films. Their lifetime is approximately three times longer than that of the Al-0.5wt.%Cu films tested at a current density of 5 × 107 A/cm2 and a temperature of 200°C. Moreover, the 4-layered films were easily etched in reactive ion etching and fine-dimensional control was realized during the pattern replication for high-frequency SAW devices. For the 4-layered films, an optimum Mo quantity and sputtering parameters were very significant for high EM reliability.
Similar content being viewed by others
References
Takagaki Y. and Ploog K.H., Relocation of surface acoustic waves in AlxGa1−x N/GaN bilayer films on SiC substrates, Semicond. Sci. Technol., 2005, 20(8): 856.
Sung C.C. and Huang C.Y., Properties of pseudomode surface acoustic waves on ST-cut quartz substrates and the effects of the thicknesses of metallic films, Acoust. Phys., 2006, 52(3): 338.
Kimura N., Nakano M., Nakazawa M., et al., The power durability of 900 MHz band double-mode-type surface acoustic wave filters and improvement in power durability of Al-Cu thin film electrodes by Cu atom segregation, Jpn. J. Appl. Phys., 1997, 36: 3101.
Kimura N., Nakano M., and Sato K., Power durability of Al-W alloy electrodes used in RF-band surface acoustic wave filters, Jpn. J. Appl. Phys., 1998, 37(3A): 1017.
Sakurai A., Yoshino Y., and Ieki H., Epitaxially grown aluminum film on 36 degrees-related Y-cut lithium tantalate for high-power surface acoustic wave devices, Jpn. J. Appl. Phys., 1994, 33: 3015.
Sakurai A., Nakanishi H., and Yoshino Y., Epitaxially grown aluminum film on rotated Y-cut lithium niobate for high-power surface acoustic wave devices, Jpn. J. Appl. Phys., 1995, 34: 2674.
Kimura N., Nakano M., and Sato K., High power-durable RF-band SAW filters using single-crystal Al/Ti electrodes grown on 64 degrees Y-X LiNbO3 substrates, Electron. Lett., 1998, 34(1): 131.
Park D.S. and Kim Y.H., Texture enhancement of Al films on Ti underlayers by radio-frequency bias sputtering, J. Electron. Mater., 2002, 31(10): 1009.
Nakagawara O., Saeki M., and Watanabe M., Epitaxially grown aluminum films with titanium intermediate layer on theta rotated Y-X LiNbO3 piezoelectric single crystal substrates, J. Cryst. Growth, 2003, 249(3–4): 497.
Yamada J., Fabrication technology of high-frequency and high-power durable surface acoustic wave devices for mobile terminals, J. Electron. Mater. Sci., 2003, 14: 711.
Li D.M., Pan F., and Niu J.B., Ion bombardment-induced high orientation of Al/Ti films for surface acoustic wave device applications, J. Electron. Mater., 2005, 34: 1053.
Li D.M., Wang X.B., and Pan F., A study of the stress and resistivity of Al/Ti films deposited by an ion beam assisted process for surface acoustic wave device applications, Mater. Sci. Eng. A., 2006, A418: 218.
Toyoda H., Kawanoue M., and Hasunuma M., Improvement in the electromigration lifetime using hyper-textured aluminum formed on amorphous tantalum-aluminum underlayer, [in] 32th Annual Proceedings-Reliability Physics (Symposium), San Jose, CA, 1994: 178.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Li, D., Liu, M. Improved electromigration reliability of surface acoustic wave devices using Ti/Al-Mo/Ti/Al-Mo electrodes. Rare Metals 28, 554–558 (2009). https://doi.org/10.1007/s12598-009-0107-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12598-009-0107-2