Understanding of the Abrupt Resistive Transition in Different Types of Threshold Switching Devices From Materials Perspective

Abstract

In this article, we investigate dynamics of electrically driven abrupt and volatile resistive switching characteristics, which are called threshold switching (TS) characteristics, in insulator-to-metal transition NbO x switch, BTe x -based ovonic threshold switch, and Ag-based atomic switch by adopting field-induced nucleation theory. To verify field-induced nucleation phenomena in the initial electroforming and electrically driven TS processes of the TS devices, we apply constant square voltage pulses with various voltage magnitudes and measure the delay time required for the electrical switching process. During both the forming and switching processes, it is observed that all the TS devices exhibit switching delay time exponential in 1/voltage with different nucleation barrier energies ( ${W}_{{0}}$ ). In addition, we find that the ${W}_{{0}}$ for the first forming process appears to be larger than that for the subsequent switching process and the difference is observed to be greater if the formed device is crystallized and smaller if not. Moreover, we find that the effective barrier energy and the fastest speed that a device can have ( $\tau _{{0}}$ ) are closely related to switching speed of the TS devices. Also, we reveal that the hold voltage characteristics are affected by the ${W}_{{0}}$ and carrier concentration of the solid electrolyte.