A NEW LEAD-FREE (K,Na)NbO3 PIEZOELECTRIC MATERIAL AND ITS MICROFABRICATION FOR MICRO ENERGY HARVESTER

In this paper, a new lead-free piezoelectric (K,Na)NbO3 (KNN) film is presented as a promising, environment-friendly alternative to the conventional piezoelectric thin film materials like PZT, etc. with regard to applying into piezo-MEMS devices in general and micro-energy-harvesting devices in particular. The KNN films deposited by the RF magnetron sputtering deposition system were revealed excellent transverse piezoelectric coefficient of 120pm/V and high figure of merit (FOM) of . The microfabrication of KNN films was investigated by both dry etching and wet etching while there are few publications about etching the material. Under the FAB condition – 3kV anode-cathode voltage, 25mA current, and 5.6sccm SF6 flow rate, the KNN-etching rate is approximately 10nm/min. Wet etching is also studied as an alternative method. Various high-concentration HF solutions are delved into etching KNN thin film. The 77nm/min KNN-etching rate in 40% HF solution is achieved.