Direct integration of piezoactuator array with active-matrix oxide thin-film transistors using a low-temperature solution process

Abstract The integration of a thin-filmpiezoelectric actuator with standard CMOS (Complementary Metal-Oxide-Semiconductor) technology has attracted many practical interests for totally integrated smart devicessuch as electronics, microfluidics, sensors and actuators. However, the major obstacle of the integration lies in high annealing temperature required for crystallization of piezoelectric thin-films(600–750 °C), which leads to degradation of back circuitry. This paper reports, for the first time, a successful direct integrationof lead-zirconium-titanate (PZT) thin-film, the piezoelectric with the greatest commercial applicability, with an active-matrix oxide thin-film transistor(TFT) using a low-temperature (450 °C) solution-processablePZT thin-film. The actuation of the PZT actuator array, electrically driven by the active-matrixTFT, was confirmed. The proposed device can be used in various applications such as micropumps/valves, microfluidic control, energy harvesting, sensors and the like.