Demonstration of an Al$_{\text{2}}$O$_{\text{3}}$ Bidirectional Selector With an Ultralarge Selectivity of 10$^{\text{9}}$

In this study, a bidirectional selector fabricated using a dielectric material of AlO $_{\textit{x}}$ is demonstrated. One single AlO $_{\textit{x}}$ film is used as the active layer of the selector. The Al/AlO $_{\textit{x}}$ /n $^{+}$ -Si selector can turn on either by a positive or negative voltage, showing a bidirectional operation feature. In addition, the selector characteristics in the positive and negative voltage regions are highly symmetric. The selectivities are both 10 $^{\text{9}}$ . Data volatility and resistive switching (RS) behavior of the Al/AlO $_{\textit{x}}$ /n $^{+}$ -Si selector are verified by investigating current–voltage characteristics under different measurement conditions. High stability of the selector is confirmed by examining read-endurance and read-disturb immunity characteristics. Turn-on/turn-off slopes, switching speed, and recovery time are also studied.