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Abstract
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| For the last few decades surface acoustic wave devices have been used not only for wireless communication systems, but also for gas, temperature and pressure sensors due to their intrinsic energy confinement in a narrow region underneath the surface. Due to the sensitivity increases when the frequency is higher, this is one of the most important factors in the selection of a suitable substrate for SAW sensors. In order to achieve higher frequencies, either the selection of a suitable material with higher phase velocity or a smaller IDT period must be considered. Aluminium nitride (AlN) deposited on chemical vapour deposition diamond is a very attractive structure for high frequency SAW devices. The main problem of synthetic diamond is its high surface roughness that worsens the sputtered AlN quality and hence the device response. We have then analysed the influence of the surface roughness on the crystal quality of the sputtered thin AlN film and device response. Moreover, in this work we use a 20 µm thick nanocrystalline diamond free standing film, whose silicon substrate was removed by chemical etching, to fabricate high frequency SAW resonators operating in the 10-14 GHz frequency range. This structure not only allows depositing high c-axis oriented AlN due to the low surface roughness of the nucleation side, but also the membrane is free to move so it provides pressure sensitivity. A SAW based sensor pressure with a sensibility of 3 Mhz/bar has been fabricated. | |
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International
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No |
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Congress
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Cursos y Seminarios del ISOM |
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Entity
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ISOM-UPM |
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Entity Nationality
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Sin nacionalidad |
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Place
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Madrid, España |
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Start Date
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11/05/2012 |
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End Date
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11/05/2012 |