Multilevel Resistive-Change Memory Operation of Al-Doped ZnO Thin-Film Transistor

A multilevel resistive-change memory device with thin-film transistor (TFT) structure is proposed, in which both functions of transistor and nonvolatile memory can be performed. Al-doped ZnO was employed for the active channel of the TFT as well as for the resistive-change material of the memory device. Multilevel memory operations could be realized by controlling the number of conducting filaments within the channel. Sound TFT characteristics and nonvolatile memory functions were demonstrated. The programmed current ratios for three-level memory states were 1:3.8:25. As results, long-time stability (10
⁴
s) and program endurance (100 cycles) for the three-level memory states were also confirmed.