The resistance switching characteristics of stoichiometric ZrO2 film were investigated for nonvolatile memory. The Al∕ZrO2∕Al device presents reliable and reproducible switching behaviors. The on/off ratio of two stable states is larger than 2×103. It is suggested that the current-voltage characteristics are governed by the Schottky conduction mechanism in high voltage region, while the filament conduction is suggested in low voltage region. The switching process is explained in terms of the spontaneous reversible reaction between electrode and ZrO2 films with the contribution of Joule heating effect by the external current. It provides a possible solution for low device yield of nonstoichiometric oxides.

The compliance-current dependence of the resistiveswitching behaviors is investigated in TaN/Cu x O/Cu memory devices with 1R architecture and 1T1R architecture, respectively. The correlation of reset current I reset and ON-state resistance R on can be verified by adjusting the compliance current I comp . Meanwhile, I reset and R on become independent on I comp in the 1R architecture when I comp is below 1 mA. A serious compliance-current overshoot phenomenon is in situ observed in 1R-architecture device, and it remarkably affects the resistive-switching characteristics because the compliance current dominates the memory behaviors. Therefore, resistive-switching investigation based on 1T1R architecture is much more reliable.

It is found that the voltage drop across a 170-nm-thick Pb(Zr0.4Ti0.6)O3 film keeps constantly at a well-defined coercive voltage during domain switching, irrespective of the applied voltage and frequency, and that the switching current of domains is reversely proportional to the resistance of loading resistors in the circuit. A simple formalism is derived for the speed of polarization reversal short into a few nanoseconds. The maximum speed of domain switching is limited by the time of compensation charge dissipation via loading resistors in the circuit, instead of reverse domain nucleation and growth. However, in most cases, the switching current decays with time and is thus peaked under different applied voltages, as observed in an 87-nm-thick film. This phenomenon is understood from our work due to the presence of interfacial passive layers that modulate switching current transient through the circuit RC-time constant, besides the consideration of a broad coercive-voltage distribution in a genuine thin film.