Inside the ovonic threshold switching (OTS) device based on GeSbSeN: Structural analysis under electrical and thermal stress

In this article, we present the structural investigation by Raman spectroscopy of GeSbSeN ovonic threshold switching (OTS) material once integrated in selector devices featuring a top electrode based on a transparent and conductive indium tin oxide layer. The devices are characterized by standard electrical protocols, and the structural evolution of the material is investigated after several switching operations. The results are correlated with the spectra obtained from blanket samples annealed at increasing temperature and are supported by XRD and TEM analyses. We establish a link between the evolution of the material structure with the annealing process and the device behavior along cycling, bringing important advancement in the understanding of the switching mechanism and of the origin of the failure in OTS devices.