IBS-Research Center for Functional Interfaces, Seoul National University, Seoul 151-747, Republic of Korea.
Nanotechnology. 2012 Aug 10;23(31):315202. doi: 10.1088/0957-4484/23/31/315202.
To initiate resistance switching phenomena, it is usually necessary to apply a strong electric field to a sample. This forming process poses very serious obstacles in real nanodevice applications. In unipolar resistance switching (URS), it is well known that the forming originates from soft dielectric breakdown. However, the forming in bipolar resistance switching (BRS) is poorly understood. In this study, we investigated the forming processes in Pt/Ta₂O₅/TaOx/Pt and Pt/TaOx/Pt nanodevices, which showed BRS and URS, respectively. By comparing the double- and single-layer systems, we were able to observe differences in the BRS and URS forming processes. Using computer simulations based on an 'interface-modified random circuit breaker network model', we could explain most of our experimental observations. This success suggests that the BRS forming in our Pt/Ta₂O₅/TaOx/Pt double-layer system can occur via two processes, i.e., polarity-dependent resistance switching in the Ta₂O₅ layer and soft dielectric breakdown in the TaOx layer. This forming mechanism can be used to improve the performance of BRS devices. For example, we could improve the endurance properties of Pt/Ta₂O₅/TaOx/Pt cells by using a small forming voltage.
为了引发电阻切换现象，通常需要在样品上施加强电场。这个形成过程在实际纳米器件应用中存在非常严重的障碍。在单极电阻切换 (URS) 中，众所周知，形成源于软击穿。然而，双极电阻切换 (BRS) 的形成过程还不太清楚。在这项研究中，我们研究了分别表现出 BRS 和 URS 的 Pt/Ta₂O₅/TaOx/Pt 和 Pt/TaOx/Pt 纳米器件中的形成过程。通过比较双层和单层系统，我们能够观察到 BRS 和 URS 形成过程的差异。使用基于“界面改性随机断路器网络模型”的计算机模拟，我们能够解释我们的大部分实验观察结果。这一成功表明，我们的 Pt/Ta₂O₅/TaOx/Pt 双层系统中的 BRS 形成可以通过两个过程发生，即 Ta₂O₅ 层中的极性相关电阻切换和 TaOx 层中的软击穿。这种形成机制可用于改善 BRS 器件的性能。例如，我们可以通过使用较小的形成电压来提高 Pt/Ta₂O₅/TaOx/Pt 单元的耐久性。
