Search

In this paper, the transition rate (TR) from the high-resistance state to the low-resistance state of a HfO2-based resistive random access memory (RRAM) is investigated. The TR is statistically characterized by applying constant voltage stresses in the range from 0.45 to 0.65 V. It is found that TR follows a voltage dependence which closely resembles the one exhibited by metal-insulator-semiconductor / metal-insulator-metal structures when subjected to constant voltage stress, but with remarkably different fitting parameters. This result suggests a common underlying mechanism in both evolutionary behaviors. Furthermore, the investigation provides additional evidence supporting the micro-structural changes in the oxide after the forming step as well as the role played by the atomic species during the SET event. [ABSTRACT FROM AUTHOR]

The impact of the dielectric thickness, forming polarity, and current compliance on the self-rectifying current–voltage ( I – V ) characteristics of Ni/HfO2/n+-Si resistive random access memory (RRAM) devices was investigated. The obtained results indicate that these three aspects not only play a role in the postforming currents but also affect the switching properties of the devices. In the case of 5-nm-thick oxide devices, a self-rectifying ratio of about three orders or magnitude is observed after substrate injection forming (SIF) with current compliance below 500 $\mu$ A. However, similar devices subjected to gate injection forming (GIF) do not exhibit such rectifying feature. This distinctive behavior for SIF is ascribed to the formation of a Schottky-like contact in between the Ni-based conducting filament and the semiconductor electrode. For 20-nm-thick oxide devices, the forming voltage under GIF and the subsequent dielectric degradation are higher than for thinner oxide layers, resulting in a less resistive state, and a negligible role of the referred Schottky barrier. The effect of the temperature on the diffusion of the Ni ions that form the conducting path is also discussed. [ABSTRACT FROM PUBLISHER]