23:T511,In this work, we report a method to enlarge the trapezoidal cantilever-based harvester power by using the high-performance Sc _0.2 Al _0.8 N/aluminum nitride (AlN) composite film and introducing symmetrical corners to both sides of the beam. Energy harvesters with variable beam structure and piezoelectric film are designed and evaluated by simulations and experiments. The trapezoid with corners (TWCs) cantilever is verified to improve the output power by a factor of five times when compared with the conventional trapezoidal cantilever without corners. The maximum power density of the ScAlN/AlN-based TWC cantilever harvester is about twice that of the AlN-based harvester, reaching 2.054 mW ·g ^-2 ·cm ^-3 at a frequency of 330.25 Hz. The optimization of piezoelectric film and structure can give an inspiration for further improving the performance of cantilever-based energy harvesters.24:T53d,This work proposes a miniaturized piezoelectric MEMS accelerometer based on polygonal topology with an area of only 868 × 833 μm². The device consists of six trapezoidal cantilever beams with shorter fixed sides. Meanwhile, a device with larger fixed sides is also designed for comparison. The theoretical and finite element models are established to analyze the effect of the beam's effective stiffness on the output voltage and natural frequency. As the stiffness of the device decreases, the natural frequency of the device decreases while the output signal increases. The proposed polygonal topology with shorter fixed sides has higher voltage sensitivity than the larger fixed one based on finite element simulations. The piezoelectric accelerometers are fabricated using Cavity-SOI substrates with a core piezoelectric film of aluminum nitride (AlN) of about 928 nm. The fabricated piezoelectric MEMS accelerometers have good linearity (0.99996) at accelerations less than 2 g. The measured natural frequency of the accelerometer with shorter fixed sides is 98 kHz, and the sensitivity, resolution, and minimum detectable signal at 400 Hz are 1.553 mV/g, 1 mg, and 2 mg, respectively. Compared with the traditional trapezoidal cantilever with the same diaphragm area, its output voltage sensitivity is increased by 22.48%.25:T4ef,With increasing requirements for massive sound acquisition, piezoelectric MEMS microphones (PMMs) have attracted widespread attention due to the advantages of low power consumption, fast response, waterproof and dustproof. This work presents a PMM with sector-connected cantilevers, where the anchors are located at the center of a circular operating area of 0.5-mm2. According to theoretical analysis and finite element simulations, the proposed PMM exhibits higher sensitivity compared with conventional cantilever diaphragms fixed at the perimeter. The PMM is fabricated on a customized cavity silicon-on-insulator (CSOI) substrate with a 9.5% scandium-doped aluminum nitride (ScAlN) film. The output of the PMM assembly is amplified and filtered from 100-Hz to 20-kHz, and the measured sensitivity, minimum detectable pressure (MDP), resolution, total harmonic distortion (THD), and signal-to-noise ratio (SNR) are −37.6-dB (re: 1-V/Pa), 40-dB SPL, 40-dB SPL, 0.997%, and 54.2-dB at 1-kHz, respectively. The calculated nonlinearity of the PMM is less than 0.85% under 94-dB SPL. The receiving sensitivity and SNR of the ScAlN-based PMM are effectively improved, which shows great potential in intelligent voice acquisition and control scenarios. [2023-0110]

#	Concept	H-Index	Publications	Citations
1	Engineering	2	2	73
2	Electrical Engineering	2	2	73
3	Mechanical Engineering	2	2	73
4	Microelectronics	2	2	73
5	Sensors	1	1	41

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