Circular test structure for the determination of piezoelectric constants of Sc x Al 1−x N thin films applying Laser Doppler Vibrometry and FEM simulations

Mayrhofer, P. M.; Euchner, Holger; Bittner, A.; Schmid, U.

doi:10.1016/j.sna.2014.10.024

Cited by 33 publications

(18 citation statements)

References 32 publications

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“…The C 33 elastic constant decreases, which is minimized near the critical composition for wurtzite to rocksalt, are attributed to the higher-volume wurtzite structure, while the piezoelectric stress constant e 33 increases with a maximum corresponding to the wurtzite-to-HBN critical composition. The results qualitatively agree with previous calculations of the elastic properties [35,37,62,63] and piezoelectric properties [35,37], while simultaneously extending the range of alloy space examined, which is necessary to accurately determine the decoupled nature of the responses. The results agree with the observed softening [22,64] and enhanced piezoelectric strain values [31,[65][66][67] of compositions studied in the literature.…”

Section: A Computationsupporting

confidence: 86%

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Talley

Millican

Mangum

et al. 2018

Phys. Rev. Materials

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An understanding of the heterostructural implications on alloying in the aluminum nitride-scandium nitride system (Al 1−x Sc x N) can highlight opportunities and design principles for enhancing desired material properties by leveraging nonequilibrium states. The fundamental thermodynamics, and therefore composition-and structuredependent mechanisms, underlying property evolution in this system have not been fully described, despite significant recent efforts driven by interest in enhanced piezoelectric performance. Practical realization of these enhanced properties, however, is hindered by the strong driving thermodynamic driving force for phase separation in the system, highlighting the need for increased study into the role of heterostructural alloying on the thermodynamics and composition-structure-property relationships in this system. With this need in mind, ab initio computed alloy thermodynamics and properties are compared to combinatorial thin-film synthesis and characterization to develop a more complete picture of the structure and property evolution across the Al 1−x Sc x N composition space. The combination of structural frustration and a flattened free-energy landscape lead to substantial increases in electromechanical response. The energy scale of alloy metastability is found to be much larger than previously reported, helping to explain difficulties in achieving homogeneous materials with high scandium concentration. Scandium substitution for aluminum softens the wurtzite crystal lattice, and energetic proximity to the competing hexagonal boron-nitride structure enhances the piezoelectric stress coefficient. Overall, this work provides insight into the understanding of the structure-processing-property relationships in the Al 1−x Sc x N system, suggests material design strategies for even greater property enhancements, and demonstrates the increased property tunability and underexplored nature of nonequilibrium heterostructural alloys.

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Section: A Computationsupporting

confidence: 86%

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Talley

Millican

Mangum

et al. 2018

Phys. Rev. Materials

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“…[8][9][10][11][12][13][14] Enhancements of more than 400% have been measured for the longitudinal and transversal response to stress, d 33 and d 31 , respectively. 15 The underlying reason for this profound change in properties is understood to be the presence of a metastable hexagonal phase in ScN.…”

mentioning

confidence: 99%

Stress controlled pulsed direct current co-sputtered Al_1−xSc_xN as piezoelectric phase for micromechanical sensor applications

et al. 2015

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“…Figure 2a shows a comparison between the absolute impedance ( ) spectrum of multiple AlN and ScAlN-based SMR devices. The series resonance frequency is lower for the ScAlN-based device, which can be directly attributed to the ~30% lower stiffness constant of ScAlN compared to AlN [14]. This results in a ~17% lower longitudinal acoustic velocity because ∝ .…”

Section: Methodsmentioning

confidence: 95%

Scandium Aluminium Nitride-Based Film Bulk Acoustic Resonators

Schneider

DeMiguel-Ramos

Flewitt

et al. 2017

Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017

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Film bulk acoustic resonators (FBAR) are promising candidates to replace surface acoustic wave devices as filters or delay lines, but also offer exciting opportunities as biological or gas sensors. In this work, solidly mounted FBARs were manufactured by substituting commonly used pure aluminium nitride (AlN) by scandium doped aluminium nitride (ScAlN) thin films as the piezoelectric layer. The ScAlN-based resonators feature a significant improvement of the electromechanical coupling factor from ~3% to ~12% compared to the pure AlN, while the decreased stiffness of ScAlN results in a decrease of the quality factor from ~300 to ~100 due to increased damping losses in the piezoelectric material.

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Circular test structure for the determination of piezoelectric constants of Sc x Al 1−x N thin films applying Laser Doppler Vibrometry and FEM simulations

Cited by 33 publications

References 32 publications

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Stress controlled pulsed direct current co-sputtered Al_1−xSc_xN as piezoelectric phase for micromechanical sensor applications

Scandium Aluminium Nitride-Based Film Bulk Acoustic Resonators

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Circular test structure for the determination of piezoelectric constants of Sc x Al 1−x N thin films applying Laser Doppler Vibrometry and FEM simulations

Cited by 33 publications

References 32 publications

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Stress controlled pulsed direct current co-sputtered Al1−xScxN as piezoelectric phase for micromechanical sensor applications

Scandium Aluminium Nitride-Based Film Bulk Acoustic Resonators

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Product

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About

Stress controlled pulsed direct current co-sputtered Al_1−xSc_xN as piezoelectric phase for micromechanical sensor applications