Suppressing current leakage and voltage drift in indium-modified electrical switching devices

Abstract

Ovonic threshold switching (OTS) devices are essential selectors for high-density memory arrays, but their operational reliability is often limited by threshold-voltage (Vth) drift arising from structural relaxation in amorphous chalcogenides. Although widely reported, the atomic mechanism behind V th drift remains insufficiently understood, limiting the rational design of highly stable OTS devices. Here we investigate the atomic origin of V th drift in In-Te OTS devices (InTe 4 , InTe 3 , and In 3 Te 7 ) and demonstrate that reducing homopolar Te-Te bonding effectively suppresses structural relaxation and V th drift. A higher In content lowers leakage current, V th , and significantly suppresses V th drift. The optimized In 3 Te 7 devices achieve an on/off ratio of ~10 5 , a low V th drift coefficient of 26 mV/dec and endurance exceeding 10 8 cycles.Ab initio molecular dynamics (AIMD) simulations further demonstrate that a portion of Te-Te homopolar bonds gradually disappear during structural relaxation and that increased In content suppresses both homopolar bonding and the formation of overcoordinated Te atoms, which are responsible for defect states inside the bandgap. This study clarifies the origin of V th drift and provides a practical material-engineering strategy for developing reliable OTS selectors for future 3D memory technologies.