Microstructure and mechanical properties of stress-tailored piezoelectric AlN thin films for electro-acoustic devices

Reusch, Markus; Cherneva, Sabina; Lu, Yuan; Žukauskaitė, Agnė; Kirste, Lutz; Holc, Katarzyna; Datcheva, Maria; Stoychev, D.; Lebedev, V.; Ambacher, O.

doi:10.1016/j.apsusc.2017.02.147

Cited by 37 publications

(31 citation statements)

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“…In order to examine the microstructure of the Al 1−x Sc x N, SEM was used for planar and cross‐sectional imaging of the samples. Typically, the well c ‐axis oriented Al 1−x Sc x N shows pebble‐like surface morphology . Figure (a) and (b) show the films grown with N 2 /(Ar + N 2 ) = 50% concentration.…”

Section: Resultsmentioning

confidence: 99%

“…Previous studies already discussed a lot about the characterization of high quality AlN and AlScN: typically, such films would have pebble‐like surface morphology and homogeneous columnar structure can be observed in cross‐section. Additionally, 000 l ( l = 2, 4, 6) reflections in XRD 2 θ / θ scan and low rocking curve FWHM values indicate high degree of c ‐axis orientation.…”

Section: Discussionmentioning

confidence: 99%

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Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Reusch

Kurz

et al. 2017

Physica Status Solidi (a)

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Reactive pulsed DC magnetron co‐sputtering is used to grow piezoelectric aluminum nitride (AlN) and aluminum scandium nitride (AlScN) thin films on Si(001) substrates. By using grazing incidence X‐ray diffraction (GIXRD), scanning electron microscopy (SEM), and piezoresponse force microscopy (PFM), we investigate how the microstructure and the presence of misoriented grains affect the piezoelectric properties of the material. N2 concentration and target‐to‐substrate distance are finely tuned to achieve thin films without misoriented grains, resulting in Al0.87Sc0.13N thin films with low roughness, high degree of c‐axis orientation, homogenous polarity, and piezoelectric coefficient d33 = −12.3 pC/N.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Surface Morphology and Microstructure of Pulsed DC Magnetron Sputtered Piezoelectric AlN and AlScN Thin Films

Reusch

Kurz

et al. 2017

Physica Status Solidi (a)

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“…A typical SEM image of (a) top view and (b) cross‐section of the AlScN thin films is shown in Figure . Based on cross‐sectional view, all investigated films have a well‐ordered columnar microstructure typical for sputtered AlN thin films …”

Section: Resultsmentioning

confidence: 99%

Temperature Dependence of the Pyroelectric Coefficient of AlScN Thin Films

Kurz

Kirste

et al. 2018

Physica Status Solidi (a)

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The piezoelectric and pyroelectric properties of aluminum nitride (AlN) can be further enhanced by alloying AlN with scandium nitride (ScN). However, while the pyroelectric effect can strongly affect the performance of electroacoustic devices such as surface acoustic wave (SAW) resonators, the pyroelectric properties of aluminum scandium nitride (AlScN) and their thermal dependence are not well known. In this work, the crystallographic, microstructural, and pyroelectric properties of 900 nm thick pyroelectric Al 1Àx Sc x N thin films (x ¼ 0 to 0.3) are investigated. All films have wurtzitetype crystal structure and are highly c-axis oriented. The pyroelectric coefficient in the temperature range of 20-80 C is determined by measuring the generated current as a function of sinusoidal temperature excitation. The effective pyroelectric coefficient of AlScN increases by approximately 85% in the investigated composition range. Moreover, no temperature dependence of the effective pyroelectric coefficient is observed for all samples. The increase of the effective pyroelectric coefficient is explained qualitatively by considering the contribution of primary and secondary pyroelectric effect as well as the substrate clamping.

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“…All the previous studies have given a very wide range for Young's modulus ranging from 204 GPa [19] to 396 GPa [15], due to the differences in the test methods and tested films. Moreover, the fatigue behavior or the fracture strength of thin film AlN, and their effects on reliability have not been studied previously.…”

Section: Introductionmentioning

confidence: 99%

“…So far, these gaps in knowledge have hindered the commercial utilization of AlN, especially in piezoelectric MEMS devices. [19][20][21], as well as microbending [22,23], microcompression [24,25] and microtensile testing [22,26], and shaft loading [27].…”

Section: Introductionmentioning

confidence: 99%