Ovonic Threshold Switch Chalcogenides: Connecting the First-Principles Electronic Structure to Selector Device Parameters

Abstract

Chalcogenides are attractive materials for microelectronics applications due to their ability to change physical, optical, and electrical properties under applied electric stimulus. One of the most recent interest in chalcogenides is their use to enable the development of a two-terminal selector device, which is a fast, volatile, resistance switching device. The electrical signature of Ovonic threshold switching (OTS) chalcogenide materials is well suited for such applications. While there are numerous known OTS materials, most of them contain toxic elements. There is hence a need to find environment-friendly OTS materials. For this to happen, we strive to predict electrical device parameters only from atomistic first-principles simulations of the chalcogenide materials, as this can be a faster and less expensive route to screen the performances of chalcogenide candidates. By mapping the experimentally measured set of electrical OTS materials into atomistic models and computing their electronic properties, we were able to identify correlations between computed properties such as the theoretical trap/mobility gaps, the local atomic coordination environments of the elements adopted in the material, and the experimentally measured first-fire/threshold/hold voltages, hold/leakage currents, or extracted trap density. These findings can guide in identifying OTS materials with predefined electronic properties, tailored to the requirements of specific microelectronics applications with only first-principles simulations.