Mobile Ionic Field Effect Transistors with Amorphous Dielectrics: Device Demonstration and Modeling

We have reported ferroelectric (FE)-like behaviors with an amorphous (a-) ZrO2. The physical origin of the FE-like behaviors is systematically investigated by electrical characterization, and confirmed to be the movement of mobile ions existing in the amorphous thin film. A physics-based model for the mobile-ionic field-effect transistor (MIFET) predicts the ferroelectric-type hysteresis and steep subthreshold slope characteristics, which have been demonstrated in an experiment using fabricated MIFET with a-ZrO2 film. Thanks to the modulation of mobile ion, analog synapse based on ZrO2 MIFET exhibits superior symmetry and linearity for both potentiation and depression, has been successfully demonstrated for spiking neural network (SNN) applications. Due to the outstanding property of a-ZrO2, the MIFETs exhibit higher endurance, lower thermal budget, and better scalability than FeFETs with crystallized doped-HfO2, indicating a novel technology for memory and computing applications.