A Study of Novel Electrochemical Displacement Copper Technique for Resistive Switching Memory Applications

• Main Authors: Lin, Li-Min, 林立民
• Other Authors: Yang, Wen-Luh
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/69867818812717220871

博士 === 逢甲大學 === 電機與通訊工程博士學位學程 === 105 === Based on the development of semiconductor processing technology, sundry novel consumer electronic products have been announced, and thus bring people more and more convenient life. According to the development tendency of electronic products, which lightweight, smaller size, higher speed, and low cost, the critical dimension of nonvolatile memories (NVMs) device has entered the nanoscale technology node. However, the conventional float-gate flash memory will face extreme technical and physical limitations when the critical dimension is continually downsizing. Therefore, various next-generation nonvolatile memories have been width studied in recent years. Among them, the resistive-switching random access memory (ReRAM) is considered as a potential candidate to replace traditional flash memory because of its advantageous particularities of simple metal-insulator-metal structure, high scalability, low power consumption, excellent reliability, and fast operation speed. In this research, a novel electrochemical displacement copper technique (Cu-CDT) has been investigated for ReRAM applications. Compared with other conventional Cu deposition techniques, the Cu-CDT exhibits numerous advantages including simplicity, low cost, low-temperature fabrication, better step coverage, and high displacement selectivity. Based on our research foundations of the previous electrochemical displacement copper in the back-end-of-line (BEOL) interconnect, the advanced Cu-CDT was proposed and further applied in a nanoscale-crossbar resistive bi-layer device with the capacity to resistive-switching memory. The poly-Si in the top electrode was completely displaced by Cu after chemical displacement using the Cu-CDT, and the Si3N4–SiO2 bi-layer remained intact by high-resolution transmission electron microscopy (HR-TEM) and energy dispersive spectroscopy (EDS) analysis revealing. This demonstrates that the Cu-CDT has a high displacement selectively for both poly-Si and Si3N4/SiO2 materials. Besides, the nanoscale-crossbare Cu-CDT ReRAM device demonstrated stable switching, high uniformity, and data retention at 85 °C. The proposed technique overcomes the difficulty of traditional Cu dry etching through its high-density crossbar architecture. Furthermore, the size of the Cu-CDT ReRAM can be continuously scaled down with the evolution of lithography technology. Based on these advantages, the proposed Cu-CDT can be effectively applied in high-density integrated ReRAM.