Fabrication and characterization of self-rectifying vertical structured resistive switching memory device

Abstract

Recent advances in data processing electronic device have shown large potential of establishing a high performance electronic system for the future generation such as IoT and neuromorphic system. The data processing electronic device called memory can be integrated with other electronic devices such as RFIDs, Solar cells, flexible displays, e-papers, flexible sensors and e-skins. Therefore, the memory is the key component of establishing an electronic system. Nonetheless, integrating memory device with other electronics is a complicated issue. Considering current chip size, memory device should be densely packed in a small chip to be interconnected with other electronic components. To satisfy the chip design, scaling down process also needed to be improved. Although the scaling down process of the memory device was carried out following Moore’s law for the last few years, it has reached its limit due to physical and electrical limit of silicon devices and need a breakthrough for the future generation electronics. To solve this problem, a large number of research groups have been reported new nonvolatile memory devices based on resistive switching materials, phase change materials, ferroelectric materials. Many of these reported devices are fabricated in crossbar structure in order to increase the density of memories in a wafer which is suitable for large scale integration (LSI), Herein, a simple method is demonstrated for fabrication of self-rectifying vertical structured resistive switching memory and its characterization analysis. By stacking memory cells in vertical direction the device density of RRAM can be improved and the deposition of thin nickel interlayer between $TiO_2$/TiOx interfaces improved the ON/OFF ratio by one order magnitude. The electrical characteristic of the device proved that the resistive switching mechanism in this device is an interface type. Furthermore, existence of rectifying characteristics with 3.88 order magnitude prevents leakage current in other unselected cells