Fabrication of Smart Material PZT Thin Films by RF Magnetron Sputtering Method in Micro Actuators

摘要

PZT piezoelectric thin films can be promising candidates for microactuators or microsen-sors in MEMS (Micro Electro Mechanical Systems) or NEMS (Nano Electro Mechanical Systems) because of the quick response. In this research, the RF magnetron sputtering method is used for PZT thin films deposition. The sputtering conditions to control the crystalline plane (111) of perovskite structure for PZT to influence the piezoelectric constant can be proposed. Those sputtering conditions such as substrate angle and temperature, Ar/O_2 pressure and flow rate were investigated by the heuristic and experimental design method to fabricate optimum PZT perovskite crystal thin film. The condition of substrate temperature was the most important factor to improve piezoelectric constant. The crystalline structure, surface topography and piezoelectric constant of the deposited PZT were observed by X-ray diffraction structural analysis, atomic force microscope and piezoelectric constant evaluation equipment. PZT thin films with only perovskite structure were obtained. PZT (111) was grown with the increase in substrate temperature, and the piezoelectric property was improved. The elastic modulus of 70 GPa for the deposited PZT found a good agreement with the quoted value for commercial based bulk PZT. We obtained a piezoelectric constant d_(31) = -28 pm/V and a high performance of bimorph actuator.