Hsu Chih-Chieh, Liu Po-Tsun, Gan Kai-Jhih, Ruan Dun-Bao, Sze Simon M
Department of Electronics Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Department of Photonics and Institute of Electro-Optical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Nanomaterials (Basel). 2021 Aug 27;11(9):2204. doi: 10.3390/nano11092204.
In this study, the influence of oxygen concentration in InWZnO (IWZO), which was used as the switching layer of conductive bridge random access memory, (CBRAM) is investigated. With different oxygen flow during the sputtering process, the IWZO film can be fabricated with different oxygen concentrations and different oxygen vacancy distribution. In addition, the electrical characteristics of CBRAM device with different oxygen concentration are compared and further analyzed with an atomic force microscope and X-ray photoelectron spectrum. Furthermore, a stacking structure with different bilayer switching is also systematically discussed. Compared with an interchange stacking layer and other single layer memory, the CBRAM with specific stacking sequence of bilayer oxygen-poor/-rich IWZO (IWZOx/IWZOy, x < y) exhibits more stable distribution of a resistance state and also better endurance (more than 3 × 10 cycles). Meanwhile, the memory window of IWZOx/IWZOy can even be maintained over 10 s at 85 °C. Those improvements can be attributed to the oxygen vacancy distribution in switching layers, which may create a suitable environment for the conductive filament formation or rupture. Therefore, it is believed that the specific stacking bilayer IWZO CBRAM might further pave the way for emerging memory applications.
在本研究中，对用作导电桥随机存取存储器（CBRAM）开关层的铟钨锌氧化物（IWZO）中的氧浓度影响进行了研究。通过在溅射过程中采用不同的氧气流量，可以制备出具有不同氧浓度和不同氧空位分布的IWZO薄膜。此外，对具有不同氧浓度的CBRAM器件的电学特性进行了比较，并用原子力显微镜和X射线光电子能谱进行了进一步分析。此外，还系统地讨论了具有不同双层开关的堆叠结构。与交换堆叠层和其他单层存储器相比，具有特定双层贫氧/富氧IWZO（IWZOx/IWZOy，x < y）堆叠顺序的CBRAM表现出更稳定的电阻状态分布以及更好的耐久性（超过3×10次循环）。同时，IWZOx/IWZOy的存储窗口在85℃下甚至可以保持超过10秒。这些改进可归因于开关层中的氧空位分布，这可能为导电细丝的形成或断裂创造合适的环境。因此，认为特定堆叠双层IWZO CBRAM可能会为新兴的存储器应用进一步铺平道路。
