Department of Materials Science and Engineering and Inter-University Semiconductor Research Center , Seoul National University , Seoul 08826 , Republic of Korea.
ACS Appl Mater Interfaces. 2019 Oct 23;11(42):38910-38920. doi: 10.1021/acsami.9b10891. Epub 2019 Oct 9.
Chalcogenide materials have been regarded as strong candidates for both resistor and selector elements in passive crossbar arrays owing to their dual capabilities of undergoing threshold and resistance switching. This work describes the bipolar resistive switching (BRS) of amorphous GeSe thin films, which used to show Ovonic threshold switching (OTS) behavior. The behavior of this new functionality of the material follows filament-based resistance switching when Ti and TiN are adopted as the top and bottom electrodes, respectively. The detailed analysis revealed that the high chemical affinity of Ti to Se produces a Se-deficient GeSe matrix and the interfacial Ti-Se layer. Electroforming-free BRS behavior with reliable retention and cycling endurance was achieved. The performance improvement was attributed to the Ti-Se interfacial layer, which stabilizes the composition of GeSe during the electrical switching cycles by preventing further massive Se migration to the top electrode. The conduction mechanism analysis denotes that the resistance switching originates from the formation and rupture of the high-conductance semiconducting Ge-rich GeSe filament. The high-resistance state follows the modified Poole-Frenkel conduction.
硫属化物材料因其具有双稳的阈值和阻变开关能力，被认为是无源交叉阵列中电阻器和选择器元件的理想候选材料。本工作描述了非晶 GeSe 薄膜的双极阻变（BRS）开关特性，其曾经表现出 OVonic 阈值开关（OTS）行为。当采用 Ti 和 TiN 分别作为顶电极和底电极时，这种材料的新功能遵循基于细丝的电阻开关特性。详细分析表明，Ti 与 Se 的高化学亲和力会产生一个 Se 缺乏的 GeSe 基体和界面 Ti-Se 层。通过采用 Ti 和 TiN 作为顶电极和底电极，实现了无需电形成的、可靠的 BRS 性能，并且具有良好的保持力和循环耐久性。性能的提升归因于 Ti-Se 界面层，它通过防止更多的 Se 向顶电极迁移，在电开关循环中稳定了 GeSe 的组成。传导机制分析表明，电阻开关源自高导半导体富 GeSe 细丝的形成和断裂。高阻状态遵循修正的 Poole-Frenkel 传导。
