Selector Devices for High Density Cross-point ReRAM

ReRAM has been considered as a promising candidate to overcome scaling limits of the conventional FLASH memory due to its superior performance. To realize the high density memory, 3D cross-point array or vertical ReRAM are necessary [1]. To integrate cross-point (4F) ReRAM device array, we need to develop bi-directional selector device to suppress the sneak current path through the unselected devices. Although various selector candidates were recently reported, several problems such as insufficient current density at set/reset operations for nano-scale devices, low selectivity, and poor endurance have been raised. In this paper, we report two types of selector devices, threshold switching and multi-layered tunneling oxide for cross-point ReRAM application.