Self-compliance SET switching and multilevel TaOx resistive memory by current-sweep operation

Ta/TaO_x-based Resistive Random Access Memory (RRAM) is studied using current-sweeping (I-sweep) DC switching operation. The self-compliance SET program is achieved to prevent the device from current overshoot. The SET current and voltage are comparable with those measured by the conventional voltage-sweeping (V-sweep) operation, but better uniformity is realized. It is found that the high high-resistance-state (HRS) resistance results in lower I-sweep SET current but higher SET voltage. As opposed to the V-sweep switching process, the I-sweep SET is a gradual process. Therefore, the low-resistance-state (LRS) resistance can be controlled easily and reliably. It will be beneficial to a new multilevel cell design for high density memory applications.