A facile solution-combustion-synthetic approach enabling low-temperature PZT thin-films

A low-temperature (≤450 °C) crystallization path for the solution-derived lead zirconium titanate (PZT) thin-film, the first choice for high-density ferroelectric/piezoelectric nanodevices, has been sought for long but with limited success. In this work, we report on a facile route enabling the crystallization of PZT thin-films at 300–450 °C by using a novel solution-combustion-synthetic (SCS) approach. The SCS precursor solution consists of metal nitrates and organic fuels (tricine and/or urea) as oxidizing and reducing agents, respectively. The essential aspect of this route is that the single and intense exothermic combustion reaction between the oxidizer and fuels occurring at 234 °C provides high self-localized thermal energy, which allows for the efficient conversion of the amorphous metal-oxide gel framework into final crystallized oxides even at very low externally applied temperature. Effects of annealing conditions such as temperature and time are systematically investigated. At optimized conditions, high-quality PZT thin-films are achieved with pure perovskite phase, large remanent polarization (∼37 µC/cm2), and small leakage current (∼0.1 µA/cm2 at 600 kV/cm). Furthermore, an application of the developed low-temperature PZT film for the ferroelectric-gate memory transistor is demonstrated. The potential integration of low-temperature processed PZT layers with other active components may redefine the design concept of classical nano-microelectronic devices.