Size-driven transition of domain switching kinetics in LiNbO3 domain-wall memory

Abstract

Repetitive erasure/creation of conducting domain walls between two parallel/antiparallel domains at bipolar write voltages enables the high storage density of a ferroelectric domain-wall memory. Generally, the domain switching kinetics is described by the Kolmogorov–Avrami–Ishibashi model on the basis of domain nucleation and growth without the consideration of distributive defect pinning energies. Here, mesa-like cells were etched from single-crystal LiNbO3 thin films bonded to SiO2/Si wafers, and Pt metal contacts were deposited at their sides. The abrupt off-to-on current jump occurs at a typical domain switching time for the cell in a lateral size above 111 nm, implying the non-Kolmogorov–Avrami–Ishibashi domain switching kinetics immune to the defect pinning effect. However, the domain switching time has a broad distribution for the cell below 49 nm, implying the defect-controlled domain switching mechanism. A new model is developed to describe the size-driven transition. The reliability tests of the memory show a fast operation speed (<2 ns) and excellent reliability of on/off switching states for mass production.