Fabrication of high temperature surface acoustic wave devices for sensor applications
Fabrication of high temperature surface acoustic wave devices for sensor applications
Research into surface acoustic wave (SAW) devices began in the early 1970s and led to the development of high performance, small size and high reproducibility devices. Much research has now been done on the application of such devices to consumer electronics, process monitoring and communication systems. The use of novel materials, such as gallium phosphate (GaPO4), extends the operating temperature of the elements. SAW devices based on this material, operating at 434 MHz and up 700 °C, can be used for passive wireless sensor applications.
Interdigital Transducer (IDT) devices with platinum and different types of under-layer metallisation have been studied. All of these devices have 1.4 µm finger-gap ratio of 1:1 and were fabricated using direct-write e-beam lithography and a lift-off process. The measured S-parameter (S11) has been used to study the mass loading effect of the platinum electrodes and the turnover temperature of GaPO4 with 5° and 11° cut. The performance and long-term stability of these devices has also been studied and the results are reported in this thesis.
The analysis of the results shows that the mass loading effect can be used to predict the desired resonant frequency of the SAW devices. The results show that of three different types of underlayer, zirconium is the preferred choice over titanium or indium tin oxide with 430 °C turnover temperature. Finally, due to the metals stability and turnover temperature, the devices can be used for wireless strain sensor to detect a creep failure in a power plant but not for wireless temperature sensor.
University of Southampton
2005
Hamidon, Mohd Nizar
(2005)
Fabrication of high temperature surface acoustic wave devices for sensor applications.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Research into surface acoustic wave (SAW) devices began in the early 1970s and led to the development of high performance, small size and high reproducibility devices. Much research has now been done on the application of such devices to consumer electronics, process monitoring and communication systems. The use of novel materials, such as gallium phosphate (GaPO4), extends the operating temperature of the elements. SAW devices based on this material, operating at 434 MHz and up 700 °C, can be used for passive wireless sensor applications.
Interdigital Transducer (IDT) devices with platinum and different types of under-layer metallisation have been studied. All of these devices have 1.4 µm finger-gap ratio of 1:1 and were fabricated using direct-write e-beam lithography and a lift-off process. The measured S-parameter (S11) has been used to study the mass loading effect of the platinum electrodes and the turnover temperature of GaPO4 with 5° and 11° cut. The performance and long-term stability of these devices has also been studied and the results are reported in this thesis.
The analysis of the results shows that the mass loading effect can be used to predict the desired resonant frequency of the SAW devices. The results show that of three different types of underlayer, zirconium is the preferred choice over titanium or indium tin oxide with 430 °C turnover temperature. Finally, due to the metals stability and turnover temperature, the devices can be used for wireless strain sensor to detect a creep failure in a power plant but not for wireless temperature sensor.
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Published date: 2005
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Local EPrints ID: 465762
URI: http://eprints.soton.ac.uk/id/eprint/465762
PURE UUID: b4656333-6750-4974-b772-4df528bd0e8c
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Date deposited: 05 Jul 2022 02:54
Last modified: 05 Jul 2022 02:54
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Author:
Mohd Nizar Hamidon
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