Oxide-based selector with trap-filling-controlled threshold switching

Abstract

A cross-point memory architecture will be adopted to make the most of the suitability of resistance change memories for high integration. To achieve this, the development of a selector device that is connected in series to the memory and helps to remove the sneak path current flowing through unselected and half-selected cells is an urgent requirement. In this Letter, we developed a selector based on a simple sandwiched structure of Pt/CoO/ITO and confirmed the nonpolar threshold resistance switching that does not require the first fire process. The selector showed an excellent performance of a very small dispersion of the threshold voltages and resistance in the OFF state with the relative standard deviations of less than 2% each, as well as the quick transition between the OFF and ON states within 50 ns. The scaling law was confirmed in the current, both in the ON and OFF states, ION and Ith. It allows us to analyze ION and Ith, based on which we can reduce the area of the device. The current conduction of the Pt/CoO/ITO selector is ruled by the trap-controlled space charge limited current (SCLC), and the threshold switching from ON to OFF states and vice versa is caused by the transition from the trap-unfilled to the trap-filled SCLC and vice versa, respectively.