Increasing Trapped Carrier Density in Nanoscale GeSeAs Films by As Ion Implantation for Selector Devices in 3D-Stacking Memory

Abstract

An ovonic threshold switching (OTS) selector based on threshold switch effect is considered as a promising switching device for 3D-stacking memory. In this work, we put forward a safe and controllable method to prepare a high-performance nanoscale GeSeAs chalcogenide film by implanting As ions into sputtered GeSe. Resistance–temperature measurement manifests that the structure of GeSeAs maintains amorphous phase even at high temperature, indicating that no phase transition occurs for this selector material. Raman scattering spectroscopy indicates that the inner structure becomes more disordered after As implantation due to the change of local structure motifs. In addition, it was demonstrated that the GeSeAs-based device with 5.0 × 1015/cm2 As dose has a low threshold voltage (Vth) of 2.5 V and a high on-state current of 10 mA. The As ions can act as donors and provide more carriers originating from the nonbonding electrons in the As-centered local structures, accounting for the low threshold voltage of the GeSeAs-based selector device.