Removal of Stress Hillocks from Platinum-Alumina Electrodes Used in High-temperature SAW Devices
- Univ. of Maine, Orono, ME (United States); University of Maine
- Univ. of Maine, Orono, ME (United States)
Microwave acoustic devices operating at elevated temperatures, such as surface acoustic wave (SAW) duplexers or high-temperature sensors, require stable thin film electrodes capable of operating in such conditions. Stresses at the interface between the substrate and the thin film electrodes originated during electrode deposition and/or during device operation can foster film agglomeration, formation of whiskers, hillocks, electromigration, separation of the metal and oxide in composite electrodes, which degrade the electrode conductivity and the device’s long-term stability and performance. Thin film composite Pt-Al2O3 has been successfully used as electrodes in langasite (LGS) SAW devices and sensors up to 900 °C, but the formation of hillocks due to stress is seen as a limitation to the device long-term stability. In this work, a modified graded film deposition technique has been implemented targeting the release of film stress between the substrate and the thin film composite electrode due to fabrication and exposure to high-temperature. The technique successfully mitigated the formation of hillocks and material agglomeration as revealed by the SEM images obtained, and can be easily extended to other metallic or composite thin films.
- Research Organization:
- Univ. of Maine, Orono, ME (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- Grant/Contract Number:
- FE0026217
- OSTI ID:
- 1864973
- Journal Information:
- IEEE International Ultrasonics Symposium, Journal Name: IEEE International Ultrasonics Symposium Vol. 2019; ISSN 1948-5727
- Publisher:
- IEEECopyright Statement
- Country of Publication:
- United States
- Language:
- English
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