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, I ON and I th. It allows us to analyze I ON and I th, 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.