High temperature stability of langasite surface acoustic wave devices

To improve the temperature stability, response speed and sensitivity of surface acoustic wave (SAW) gas sensor, the relationship between the sensing region of the resonator for SAW gas sensor and the sensitivity of sensor is studied, a specific resonator with big space topology structure is proposed. A SAW resonator with high temperature stability is investigated from the viewpoint of piezoelectric material, cut type and fabrication process. A nano-wire bundle based SAW gas sensor with big specific-surface-area is proposed.

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Surface Acoustic Wave Device on (AlN/LGS) Substrate

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.53 ◽

2007 ◽

Vol 124-126 ◽

pp. 53-56

Author(s):

Sean Wu ◽

Zhi Xun Lin ◽

Maw Shung Lee

Keyword(s):

Thin Films ◽

Acoustic Wave ◽

Surface Acoustic Wave ◽

Electromechanical Coupling ◽

Chemical Properties ◽

Temperature Stability ◽

Rf Magnetron Sputtering ◽

High Temperature Stability ◽

Saw Devices ◽

Stable Chemical

Langasite (La3Ga5SiO14 or abbreviated as LGS) single crystal is an attractive substrate for surface acoustic wave (SAW) devices requiring good temperature stability and higher electromechanical coupling constant than quartz. AlN thin films are attractive materials that have some excellent characteristics, such as high SAW velocity, piezoelectricity, high-temperature stability, and stable chemical properties. In this study, AlN thin films were deposited on LGS to be a new composite SAW substrate (AlN/LGS) by reactive RF magnetron sputtering method. SAW delay-line device was manufactured on this substrate. The performance of the device was measured by network analyzer (Agilent 8753E).The results exhibited the composite substrate (AlN/LGS) increased the Rayleigh wave velocity, decreased the insertion loss of SAW devices, and suppressed the harmonic response.

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Mo-La2O3 Multilayer Metallization Systems for High Temperature Surface Acoustic Wave Sensor Devices

Materials ◽

10.3390/ma12172651 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2651 ◽

Cited By ~ 3

Author(s):

Siegfried B. Menzel ◽

Marietta Seifert ◽

Abhinav Priyadarshi ◽

Gayatri K. Rane ◽

Eunmi Park ◽

...

Keyword(s):

High Temperature ◽

Acoustic Wave ◽

Surface Acoustic Wave ◽

Lanthanum Oxide ◽

High Vacuum ◽

High Temperature Stability ◽

Multilayer Systems ◽

Si Substrates ◽

Acoustic Wave Sensor ◽

Sensor Devices

Developing advanced thin film materials is the key challenge in high-temperature applications of surface acoustic wave sensor devices. One hundred nanometer thick (Mo-La 2 O 3 ) multilayer systems were fabricated at room temperature on thermally oxidized (100) Si substrates (SiO 2 /Si) to study the effect of lanthanum oxide on the electrical resistivity of molybdenum thin films and their high-temperature stability. The multilayer systems were deposited by the magnetron sputter deposition of extremely thin (≤1 nm) La interlayers in between adjacent Mo layers. After deposition of each La layer the process was interrupted for 25 to 60 min to oxidize the La using the residual oxygen in the high vacuum of the deposition chamber. The samples were annealed at 800 ∘ C in high vacuum for up to 120 h. In case of a 1 nm thick La interlayer in-between the Mo a continuous layer of La 2 O 3 is formed. For thinner La layers an interlayer between adjacent Mo layers is observed consisting of a (La 2 O 3 -Mo) mixed structure of molybdenum and nm-sized lanthanum oxide particles. Measurements show that the (Mo-La 2 O 3 ) multilayer systems on SiO 2 /Si substrates are stable at least up to 800 ∘ C for 120 h in high vacuum conditions.

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