Future data-intensive applications will have integrated circuit architectures combining energy-efficient transistors, high-density data storage and electro-optic sensing arrays in a single chip to perform in situ processing of captured data. The costly dense wire connections in 3D integrated circuits and in conventional packaging and chip-stacking solutions could affect data communication bandwidths, data storage densities, and optical transmission efficiency. Here we investigated all-ferroelectric nonvolatile LiNbO₃ transistors to function through redirection of conducting domain walls between the drain, gate and source electrodes. The transistor operates as a single-pole, double-throw digital switch with complementary on/off source and gate currents controlled using either the gate or source voltages. The conceived device exhibits high wall current density and abrupt off-and-on state switching without subthreshold swing, enabling nonvolatile memory-and-sensor-in-logic and logic-in-memory-and-sensor capabilities with superior energy efficiency, ultrafast operation/communication speeds, and high logic/storage densities.

Among today’s nonvolatile memories, ferroelectric-based capacitors, tunnel junctions and field-effect transistors (FET) are already industrially integrated and/or intensively investigated to improve their performances. Concurrently, because of the tremendous development of artificial intelligence and big-data issues, there is an urgent need to realize high-density crossbar arrays, a prerequisite for the future of memories and emerging computing algorithms. Here, a two-terminal ferroelectric fin diode (FFD) in which a ferroelectric capacitor and a fin-like semiconductor channel are combined to share both top and bottom electrodes is designed. Such a device not only shows both digital and analog memory functionalities but is also robust and universal as it works using two very different ferroelectric materials. When compared to all current nonvolatile memories, it cumulatively demonstrates an endurance up to 10¹⁰ cycles, an ON/OFF ratio of ~10², a feature size of 30 nm, an operating energy of ~20 fJ and an operation speed of 100 ns. Beyond these superior performances, the simple two-terminal structure and their self-rectifying ratio of ~ 10⁴ permit to consider them as new electronic building blocks for designing passive crossbar arrays which are crucial for the future in-memory computing.

The downscaling of commercial one-transistor–one capacitor ferroelectric memory cells is limited by the available signal window for the use of a charge integration readout technique. However, the erasable conducting charged walls that occur in insulating ferroelectrics can be used to read the bipolar domain states. Both out-of-plane and in-plane cell configurations are compared for the next sub-10-nm integration of ferroelectric domain wall memories with high reliability. It is highlighted that a nonvolatile read strategy of domain information within mesa-like cells under the application of a strong in-plane read field can enable a massive crossbar connection to reduce mobile charge accumulation at the walls and crosstalk currents from neighboring cells. The memory has extended application in analog data processing and neural networks.

The critical dimension for reverse domain nucleation in the ferroelectric polarization switching of $\text{Pb}\left({\text{Zr}}_{0.4}{\text{Ti}}_{0.6}\right){\text{O}}_3$ (PZT) thin film was estimated experimentally from a coercive voltage estimation in $\text{Pt}/{\text{Al}}_2{\text{O}}_3/\text{PZT}/\text{Ir}$ ferroelectric thin-film capacitors with various ${\text{Al}}_2{\text{O}}_3$ thicknesses and switching currents. The critical nuclei dimension for reverse domain formation in a 300-nm-thick PZT was only $4.5\pm 0.4\text{nm}$, which is in agreement with theoretical predictions of the critical nucleus size. Almost all the coercive voltage was applied to the nucleation layer thickness during ferroelectric switching. The classical Merz’s exponential law for the domain velocity description and Laudauer’s paradox of an implausibly large nucleation energy barrier were understood in terms of the charge-injection limited domain motion described by thermionic field emission at the $\text{Pt}/{\text{Al}}_2{\text{O}}_3$ interface or Fowler-Nordheim tunneling at the Pt/PZT interface.