Fabrication and characterization of MEMS piezoelectric synthetic jet actuators with bulk-micromachined PZT thick film

In this paper, we have developed a fabrication process for micro synthetic jet actuators (SJA) by bonding a high-quality Pb (Zr,Ti) O₃ (PZT) ceramic wafer to a silicon wafer using epoxy resin at low temperature (<150 °C). The bulk-PZT was lapped and polished to be PZT thick film by chemical mechanical polishing (CMP) method, and patterned by wet-etching method. The cavity and orifice of SJA were formed by inductive coupled plasma etching (ICP) method. A MEMS piezoelectric SJA was then completed and characterized, including the performance of the PZT thick film. While the dimension of bonded PZT thick film is about 6,000 × 6,000 × 100 μm, and the dimension of Si membrane is about 1,000 × 1,000 × 20 μm. The experimental results show that the maximum center amplitude of PZT-Si diaphragm is 15.05 μm at Vp-p of 90 V and the resonant frequency of 5 kHz, and the maximum jet velocity is higher than 11 m/s. This novel process has great potential to fabricate MEMS piezoelectric synthetic jet actuators.