Fabrication and characterization of a ferroelectric-gate FET With a ITO/PZT/SRO/Pt stacked structure

We have demonstrated nonvolatile memory operation of a ferroelectric-gate thin film transistor (FGT) using solution-processed indium-tin-oxide (ITO) as a channel layer with combination of a PZT/SrRuO₃/Pt gate stacked structure. A well-defined ITO/PZT interface with atomically flat PZT surface and a negligibly compositional interdiffusion were obtained, which indicate that the use of a SrRuO₃ (SRO) buffer layer between Pt and PZT provides a homogeneous crystal orientation as well as stable perovskite structure for PZT. Furthermore, the fabricated FGT exhibits a high “ON/OFF” current ratio (I_ON/I_OFF) of 10⁶ and a large memory window of 2.5 V. Such a high current ratio is due to large carrier modulation induced by ferroelectricity of PZT. This device with excellent operation can be a good candidate for nonvolatile memory applications.