Song Bing, Cao Rongrong, Xu Hui, Liu Sen, Liu Haijun, Li Qingjiang
College of Electronic Science, National University of Defense Technology, Changsha 410073, China.
Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Science, Beijing 100029, China.
Nanomaterials (Basel). 2019 Mar 11;9(3):408. doi: 10.3390/nano9030408.
Volatile programmable metallization cell is a promising threshold switching selector with excellent characteristics and simple structures. However, the large variation of threshold voltage is a major problem for practical application. In this work, we propose a dual-layer structure to increase selectivity and improve the threshold voltage variation. Compared to single-layer devices, this dual-layer device exhibits higher selectivity (>10⁷) and better threshold voltage uniformity with less than 5% fluctuation during 200 DC switching. The improvement is attributed to good control on the location of the filament formation and rupture after introducing a HfO₂ layer. It is deduced that a major factor consists of the difference of Ag ions mobility between SiTe and HfO₂ due to the grain boundary quantity.
挥发性可编程金属化单元是一种具有优异特性和简单结构的有前途的阈值开关选择器。然而，阈值电压的大幅变化是实际应用中的一个主要问题。在这项工作中，我们提出了一种双层结构来提高选择性并改善阈值电压变化。与单层器件相比，这种双层器件表现出更高的选择性（>10⁷）和更好的阈值电压均匀性，在200次直流开关过程中的波动小于5%。这种改进归因于在引入HfO₂层后对细丝形成和断裂位置的良好控制。据推断，一个主要因素是由于晶界数量导致SiTe和HfO₂之间银离子迁移率的差异。
