In this paper, the dependence of sensing currents on various device parameters is comprehensively studied by simulating the complete crossbar array rather than its equivalent analytical model. The worst-case scenario for read operation is strictly analyzed and defined in terms of selected location and data pattern, respectively, based on the effect of parasitic sneak paths and interconnection resistance. It is shown that the worst-case data pattern depends on the trade-off between the shunting effect of the parasitic sneak paths and the current injection effect of the parasitic sneak leakage, thus requiring specific analysis in practical simulations. In dealing with that, we propose a concept of the threshold array size incorporating the trade-off to define the parameter-dependent worst-case data pattern. This figure-of-merit provides guidelines for the worst-case scenario analysis of the crossbar array read operations.

The total ionizing dose effect is experimentally investigated on the electrical characteristics of low on/off switching ratio TiO ₂ memristive memories for the first time. The ⁶⁰ Co γ-ray irradiation reduces the dispersion of the I-V curves, the resistances and the switch voltages, but the degradations of parameters have no impact on the data storage and reading/writing operations, indicating great stability to the irradiation and potential to the space applications. Furthermore, the low on/off switching ratio devices are ideal samples for the investigations of radiation effect on the memristive devices due to their observable parameter variation post the irradiation exposure.