Comprehensive scaling study of NbO₂ insulator-metal-transition selector for cross point array application

The transition metal oxide, NbO₂, which exhibits an insulator to metal transition (IMT) is regarded as a promising selector device to be integrated with a resistive memory for cross point array application. In this study, we comprehensively investigated the scaling of an NbO₂ selector using a mushroom device structure. A thorough understanding of the scaling behavior of forming voltage (V_f), threshold voltage (V_th), and current (I_th) is essential to evaluate the potential of voltage as well as current scaling and selectivity of NbO₂ selector. Importantly, by analyzing the scaling trend of threshold current, we believed that the IMT behavior is strongly affected by filamentary conducting path formed during the forming process. The findings provide the promise to maximize the selector device performance by minimizing the conducting path inside the NbO₂ layer.