Abstract
Amorphous and crystalline ZrTiO x -based metal-insulator-metal (MIM) devices were used as the platform to investigate the impact of dielectric crystallinity on the electrical performance of resistive memory devices. Without any forming step, bipolar switching behaviors can be found for devices with both types of dielectrics. However, the opposite initial state and current-voltage (I-V) hysteresis direction suggest different conduction mechanisms which are mainly determined by whether grain boundaries exist. Combining grain boundaries with a higher permittivity, devices with crystalline ZrTiO x show undesirable operation voltage fluctuation, higher current and switching voltage, and worse endurance as compared to its counterparts. On the contrary, devices with amorphous ZrTiO x are promising in realizing next-generation nonvolatile memory in terms of low operation voltages of ±1.3 V, a tight distribution of operation voltages, high operation speed of 200 ns, a large sensing margin of 218 times, robust endurance up to 10 5 cycles, and satisfactory retention performance. © 2013 Elsevier B.V. All rights reserved.