Evaluation of langasite (La3Ga5SiO14) as a material for high temperature microsystems

Ansorge, E.; Schimpf, Stefan; Hirsch, S.; Sauerwald, Jan; Fritze, Holger; Schmidt, Bertram

doi:10.1016/j.sna.2005.12.015

Cited by 28 publications

(13 citation statements)

References 5 publications

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“…To demonstrate the etching process and the potential of langasite as substrate for bulk micro-machining, micro-cantilever beams [100,101] and membranes [102,103] are designed and structured. As an example, the depth profile of a biconvex membrane is shown in Fig.…”

Section: Micro-electromechanical Structuresmentioning

confidence: 99%

High-temperature piezoelectric crystals and devices

Fritze

2011

J Electroceram

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Conventional piezoelectric materials such as quartz are widely used as high precision transducers and sensors based on bulk acoustic waves. However, their operation temperature is limited by the intrinsic materials properties to about 500 • C. High-temperature applications are feasible by applying materials that retain their piezoelectric properties up to higher temperatures. Here, langasite (La 3 Ga 5 SiO 14 ) and compounds of the langasite family are the most promising candidates, since they are shown to exhibit bulk acoustic waves up to at least 1400 • C. The mass sensitivity of langasite resonators at elevated temperatures is about as high as that of quartz at room temperature. Factors limiting potential use of those crystals include excessive conductive and viscous losses, deviations from stoichiometry and chemical instability. Therefore, the objective of this work is to identify the related microscopic mechanisms, to correlate electromechanical properties and defect chemistry and to improve the stability of the materials by e.g. appropriate dopants.Further application examples such as resonant gas sensors are given to demonstrate the capabilities of hightemperature stable piezoelectric materials. The electromechanical properties of langasite are determined and described by a one-dimensional physical model. Key properties relevant for stable operation of resonators are found to be shear modulus, density, electrical conductivity and effective viscosity. In order to quantify their impact on frequency and damping, a general-H. Fritze (B)

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Section: Micro-electromechanical Structuresmentioning

confidence: 99%

High-temperature piezoelectric crystals and devices

Fritze

2011

J Electroceram

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“…Furthermore, no phase transformation prior to its melting temperature, being on the order of 1470°C, makes it, in principle, promising for high temperature applications. [7][8][9][10] However, the electrical resisitivity of langasite crystals has been found to be less than 1 M⍀ cm at temperatures of only 700°C, significantly limiting its high temperature usage. 11 Thus, numerous studies have been carried out, in order to increase the resistivity ͑decrease conductivity͒, such as growing and annealing LGS crystals in an argon ͑Ar͒ atmosphere, minimizing the Ir crucible contamination during growth and compositional modification including strontium or aluminum.…”

Section: Introductionmentioning

confidence: 99%

“…25,26 To date, research on the ordered langasite-type crystals has been focused on room temperature piezoelectric properties and their SAW performance. [7][8][9][10] In this work, the dielectric, piezoelectric, electromechanical, mechanical, and electrical resistivities for ordered STGS, SNGS, CTGS, and CTAS crystals were characterized as a function of temperature, up to 900°C, prior to the electrode degradation.…”

Section: Introductionmentioning

confidence: 99%

Characterization of high temperature piezoelectric crystals with an ordered langasite structure

Zhang

Zheng

Kong

et al. 2009

Journal of Applied Physics

159

107

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͑CTAS͒, were studied as a function of temperature, up to 900°C. The dielectric permittivity 11 and piezoelectric coefficient d 11 of the ordered crystals were found to be on the orders of 12-16 and 4-5 pC/N, respectively, slightly lower than langasite ͑La 3 Ga 5 SiO 14 -LGS͒ or langanite ͑La 3 Ga 5.5 Nb 0.5 O 14 ͒ crystals which possess a disordered structure. The mechanical quality factor Q and electrical resistivity , however, were found to be greatly improved at elevated temperatures Ն500°C, being one to two orders of magnitude higher, due to cation ordering. Of particular interest is the CTAS crystal, in which, the Ga cations are totally replaced by low cost Al cations. Together with its thermally stable piezoelectric properties and high electrical resistivity, CTAS crystals offer a competitive material for high temperature sensing applications.

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“…However in the last decade the langasite (LGS) crystal has attracted attention for sensors operating at elevated temperature [10][11][12] because this crystal possesses high piezoelectric coupling, temperature stability and low acoustic loss [13].…”

Section: Introductionmentioning

confidence: 99%

“…More recently E. Ansorge et Al [13,14] investigated the possibility to design and to fabricate cantilever beams in Y-cut LGS. These workers fabricated beams with length varying from 1.35 mm to 4.4 mm by chemical etching.…”

Section: Introductionmentioning

confidence: 99%

Computer aided design of Langasite resonant cantilevers: analytical models and simulations

Tellier

Leblois

Durand

2010

Eur. Phys. J. Appl. Phys.

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Analytical models for the piezoelectric excitation and for the wet micromachining of resonant cantilevers are proposed. Firstly, computations of metrological performances of micro-resonators allow us to select special cuts and special alignment of the cantilevers. Secondly the self-elaborated simulator TENSOSIM based on the kinematic and tensorial model furnishes etching shapes of cantilevers. As the result the number of selected cuts is reduced. Finally the simulator COMSOL® is used to evaluate the influence of final etching shape on metrological performances and especially on the resonance frequency. Changes in frequency are evaluated and deviating behaviours of structures with less favourable built-ins are tested showing that the X cut is the best cut for LGS resonant cantilevers vibrating in flexural modes (type 1 and type 2) or in torsion mode.3

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Evaluation of langasite (La3Ga5SiO14) as a material for high temperature microsystems

Cited by 28 publications

References 5 publications

High-temperature piezoelectric crystals and devices

High-temperature piezoelectric crystals and devices

Characterization of high temperature piezoelectric crystals with an ordered langasite structure

Computer aided design of Langasite resonant cantilevers: analytical models and simulations

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