An excellent performance of a C-Te OTS device with amorphous Ge interfacial layer for selector application

Abstract

The effect of the interfacial layer on the reliability and off-current of a C-Te-based Ovonic threshold switching (OTS) device is investigated. By introducing an amorphous Ge (a-Ge) layer between both the top and bottom electrodes and the OTS film, a nearly 2-order of off-current reduction is confirmed. This could be attributed to the formation of a virtual electrode in the a-Ge layer that can scale down the effective area and localize electric field in a specific region. Area independent current-voltage characteristics were observed in the a-Ge introduced device while the without the barrier shows area dependent behavior, thus supporting the presence of a relatively small conductive filament that can act as a virtual electrode in the a-Ge inserted device. In addition, variabilities of the threshold voltage, hold voltage, and off-current are considerably improved owing to the confinement of the electric field. Transmission electron microscopy and energy dispersive spectroscopy analyses were employed to reveal the role of Ge at the interface. The findings are further supported by simulation using the thermally assisted hopping model.