Piezoelectric Thin Film Materials for Acoustic MEMS Devices

Fluid Flow to Electricity: Capturing Flow-Induced Vibrations with Micro-Electromechanical-System-Based Piezoelectric Energy Harvester

“…To protect the device and handle layers during the fabrication and prevent edge oxidation, a protective SiO2 layer, approximately 3000 Å thick, was deposited on both surfaces of the wafer via plasma-enhanced chemical vapor deposition (PECVD). For the piezoelectric component, aluminum nitride (AlN) was selected despite having a piezoelectric constant (5.5 10 −12 C/N at d33) that is approximately 100 time lower than that of lead zirconate titanate (PZT) [37,38]. This choice was made considering AlN's advantages, such as a reduced contamination risk and greater cost-efficiency [39].…”

“…The thin AlN film, covered with electrodes and deposited on the silicon cantilever beam (Figure 4g), exhibits varying physical properties based on its crystal orientation. The reactive sputtering process, employed for depositing AlN, requires careful control of the For the piezoelectric component, aluminum nitride (AlN) was selected despite having a piezoelectric constant (5.5 × 10 −12 C/N at d 33 ) that is approximately 100 time lower than that of lead zirconate titanate (PZT) [37,38]. This choice was made considering AlN's advantages, such as a reduced contamination risk and greater cost-efficiency [39].…”

“…When designing piezoelectric MEMS energy harvesters, materials like PZT and AlN are considered. Although PZT is often favored for its superior piezoelectric efficiency [38], allowing vibrational energy harvesters to generate power ranging from 1 µW to 100 µW [16][17][18], it poses specific challenges in fabrication due to contamination risks during the deposition process. Conversely, while AlN exhibits lower piezoelectric properties, it is considered more feasible for MEMS fabrication due to its ease of processing [39], typically generating power at mV levels in the nW to µW range [19,20].…”

A review of piezoelectric MEMS sensors and actuators for gas detection application

“…In fact, there are some other piezoelectric thin film materials that are being developed for FBAR devices such as gallium nitride (GaN) and ( 9) 1 barium strontium titanate (BST), particularly for high-frequency devices for communication applications. To culminate with the piezoelectric material that has been used for thin film fabrication for FBAR development, the AIN and ZnO have been strongly considered the most used and useful piezoelectric materials for fabricating FBAR devices, and the choice between both is depending on the applications and fabrication tools accessibility [292][293][294]. Furthermore, various methods have been investigated and developed for improving the quality factor, sensitivity, and performance of the FBAR sensors including the choice and development of the piezoelectric thin film material as well as the bottom and top electrode materials, optimizing the device structures, the thickness of the piezoelectric thin film, and the fabrication processes for the FBAR.…”