Ferroelectric Controlled Interfacial Effect on the Electronic Properties of PZT Gated IGZO Channel Thin-Film Transistors

The performance of nonvolatile memory has to be further enhanced in order to keep up with the quick growth of electronic devices. The present study focuses on optimizing the fabrication of Pb(Zr_0.52Ti_0.48)O₃ (PZT) epitaxial thin films and the impacts of oxygen-rich annealing on their crystal structures and ferroelectric properties. The transistor characteristics of ferroelectric PZT gated indium-gallium-zinc-oxide (IGZO)-channel thin-film transistors (i.e., PZT/IGZO transistors) are also studied. We have demonstrated that postannealing treatment significantly enhances the ferroelectric properties of PZT thin films, achieving a residual polarization of 45.4 μC/cm² and a saturation polarization of 74.2 μC/cm². High-quality PZT film is beneficial for regulating the transport properties of IGZO channel transistors. Simultaneously, the on/off ratio of the transistors is significantly enhanced through an additional annealing process in an oxygen atmosphere, approaching a magnitude of 10⁷. A polarization-controlled trapping and detrapping mechanism is tentatively proposed to explain the clockwise hysteresis observed in the transfer characteristics of the PZT/IGZO transistors.