Process Control Monitor (PCM) for Simultaneous Determination of the Piezoelectric Coefficients d31 and d33 of AlN and AlScN Thin Films

Zhang, Hao; Wang, Yang; Wang, Lihao; Liu, Yichen; Chen, Hao; Wu, Zhenyu

doi:10.3390/mi13040581

Cited by 16 publications

(12 citation statements)

References 23 publications

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“…Based on the very good agreement between the experimental data and fitted curves, we access the dependence of the Y concentration on material properties in Al 1− x Y x N films (Figure 4c). Although higher than the one of pure AlN, [ 36 ] the piezoelectric performance of the alloy films does not improve with higher Y content, as the d 33 coefficient remains constant at the value of ≈5 pm V −1 . In their previous works, Schlögl et al and Pandit et al claimed higher d 33 values 7.79 pm V −1 [ 21 ] and 7.85 pC N −1 , [ 22 ] respectively, despite the lower amount of yttrium‐based solute.…”

Section: Resultsmentioning

confidence: 99%

AlYN Thin Films with High Y Content: Microstructure and Performance

Solonenko

Strube

Fammels

et al. 2023

Physica Rapid Research Ltrs

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Pseudobinary nitride alloys display enhanced piezoelectric properties compared to their nonalloyed counterparts enabling their wide application in high‐performance transducers and acoustic wave resonators. Their fabrication remains challenging because of their inherently stochastic nature, which requires in‐depth understanding of the film growth dynamics and the interplay of deposition parameters. Herein, thin Al1−xYxN films are produced with varied yttrium content in the range from x = 0.09 to 0.28 on a gradient seed layer on 200‐mm Si substrates and investigated via various X‐ray diffraction methods, high‐resolution scanning transmission electron microscopy, nanoindentation, and atomic force microscopy. Bulk acoustic wave resonators, solidly mounted on a multilayer acoustic isolation, are fabricated to analyze the piezoelectric performance of the films and to extract corresponding material parameters via fitting of the high‐frequency electrical response by 1D Mason's model. The trend of declining coupling is explained by the lattice softening and the increase in electron density, experimentally observed by monitoring reduced elastic modulus and dielectric constant values, respectively. The absence of expected enhancement of the piezoelectric modulus is interpreted by the presence of oxygen impurities, facilitating the inhomogeneous strain of the AlYN lattice, which effectively cancels the energy flattening phenomenon, found in III–V pseudobinary alloys.

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Section: Resultsmentioning

confidence: 99%

AlYN Thin Films with High Y Content: Microstructure and Performance

Solonenko

Strube

Fammels

et al. 2023

Physica Rapid Research Ltrs

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“…The d 33 values were estimated from the measured d 33, f values via a modified version of the Berlincourt method by taking into account the clamping of the thin film to the substrate based on the following relationship: [ 70 ]

{d_{33}} = {d_{33,f}} + 2{d_{31}}\frac{{{s_{13,p}}}}{{{s_{11,p}} + {s_{12,p}}}}

…”

Section: Methodsmentioning

confidence: 99%

“…The d 33 values were estimated from the measured d 33,f values via a modified version of the Berlincourt method by taking into account the clamping of the thin film to the substrate based on the following relationship: [70]…”

Section: Methodsmentioning

confidence: 99%

Unlocking AlN Piezoelectric Performance with Earth‐Abundant Dopants

Startt

Quazi

Sharma

et al. 2023

Adv Elect Materials

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The increasing demand for high‐performance piezoelectric materials and toxicity and thermal stability issues of the widely used lead zirconate titanates (PZT) have spurred a search for better alternatives in electronic devices. In comparison to PZT, group III nitrides such as aluminum nitride (AlN), are only weakly piezoelectric, but doping AlN with scandium (Sc) improves the piezoelectric response by nearly 500%. Relative to PZT, doped‐AlN piezoelectric materials are advantageous because they are far more compatible with complementary metal–oxide–semiconductor (CMOS) materials, and they maintain both piezoelectric and thermodynamic stability up to very high temperatures. Unfortunately, rare‐earth metals are notoriously expensive, and fabricating stable films with rare‐earth dopants is also challenging, limiting their use in industrial applications. In this work, ab initio calculations are combined with targeted fabrication and experimentation to identify alternative earth‐abundant dopants for AlN from the periodic table d‐block. Amongst the 23 elements screened, it is found that group IVB metals, titanium, zirconium, and hafnium induce large piezoelectric enhancements comparable to Sc. This improvement is traced to shifts in the atomic sublattice structure and changes in the local charge states. In demonstrating a highly accessible and affordable path for technological adaptation of AlN‐based piezoelectrics, this work provides the foundation for sustainable, next‐generation electronics.

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“…Finite element modelling of the PMUTs is performed using COMSOL Multiphysics 5.6 simulation software with reference to Figure 1 and the structural parameters in Table 1. The corresponding elasticity matrix of AlN is derived according to the method mentioned in the reference [9]. The material parameters utilized are presented in Table 2.…”

Section: Simulation Analysismentioning

confidence: 99%

Characterization of AlN thin film piezoelectric coefficient d31 using Piezoelectric Micromachined Ultrasonic Transducers (PMUTs)

Zhang

et al. 2023

J. Phys.: Conf. Ser.

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The transverse piezoelectric coefficients d 31 of piezoelectric membranes is fundamental to the design, simulation, optimization, and applications of piezoelectric devices using Aluminum Nitride (AlN). In this work, a method based on the inverse piezoelectric effect is proposed to characterize d 31. Based on the piezoelectric equation and the thin film vibration equation, the central displacement of the Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) is linearly related to the DC voltages when the PMUTs are in the linear operating region. The central displacement of PMUTs is measured by 3D Measuring Laser Microscope at various DC voltages. The finite element method (FEM) is combined with change of d 31 to approximate the relationship between displacement and voltage. Then, The proposed method is verified for its accuracy through the use of the cantilever technique where the cantilever is fabricated on the same wafer as the above PMUTs. The d 31 of the AlN thin film obtained by the proposed method and the cantilever method are -1.58pC/N and -1.60pC/N. The error of the two methods is within 2%. Ultimately, the extraction and measurement of d 31 can be achieved by the proposed method.

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Process Control Monitor (PCM) for Simultaneous Determination of the Piezoelectric Coefficients d31 and d33 of AlN and AlScN Thin Films

Cited by 16 publications

References 23 publications

AlYN Thin Films with High Y Content: Microstructure and Performance

AlYN Thin Films with High Y Content: Microstructure and Performance

Unlocking AlN Piezoelectric Performance with Earth‐Abundant Dopants

Characterization of AlN thin film piezoelectric coefficient d31 using Piezoelectric Micromachined Ultrasonic Transducers (PMUTs)

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