Mitigating Hysteresis Effects in Open-Loop-Driven PZT MEMS Micromirrors with Piezoresistive Sensing

Piezoelectric materials are becoming key elements for Microelectromechanical Systems (MEMS) products, specifically for thin layers micro-actuators. At the same time, for some applications like micromirrors, it is fundamental to precisely control the actuator position. In this work, a study on hysteresis effects on 2-mu m thin layer of Lead-Zirconate-Titanate (PZT) is presented. After measuring the charge-voltage characteristic curve, four different configurations of driving and sensing of a micromirror position are tested, including charge controlled actuation, voltage-controlled actuation, piezoresistive sensing and PZT sensing. Measurements report a five-fold hysteresis reduction when using charge controlled actuation combined with piezoresistive sensing.