Total Ionizing Dose Effects of Gamma-Ray Radiation on NbO_x-Based Selector Devices for Crossbar Array Memory

The transition metal oxide NbO₂ is regarded as a promising selector device to be integrated with resistive random access memory for the high-density crossbar array architecture. Understanding its total ionizing dose (TID) response would help assess the reliability of using this selector device in radiation environments. In this paper, we investigate the TID effect of gamma-ray (γ-ray) radiation on a Pt/NbO_x/Pt selector device using electrical characterization and an X-ray photoelectron spectroscopy (XPS). The NbO_x devices were irradiated with ⁶⁰Co γ-rays to a maximum dose of 5 Mrad (NbO₂). The experimental results show that the threshold switching behavior can withstand the 5 Mrad (NbO₂) without significant change in the switching parameters. The XPS results reveal that there are mixed NbO₂ and Nb₂O₅ phases in the NbO_x thin film. After 5 Mrad (NbO₂) γ-ray irradiation, the peak intensity of NbO₂ increases and the peak intensity of Nb₂O₅ decreases in the XPS spectra, probably due to the reduction of Nb₂O₅ under radiation. Nevertheless, the electrical properties of the NbO_x-based selector have remained after 5 Mrad (NbO₂) γ-ray irradiation, indicating the potential use of the NbO_x-based selector device in aerospace applications.