Characterization of Chemical Bonding Features of Ti Oxide based ReRAM and Their Impact on Resistance-Switching Properties

为了更好地理解电阻转换的机理，研究了二氧化钛基电阻型随机存储器(ReRAM)在电阻变化后的化学键特性。用硬X射线光电子能谱观察了电阻转换后的铂电极在低阻状态下的氧化和高阻状态下的PtOx的还原。结果表明，钛氧化物基质中氧空位的产生是导致LRS的导电层形成的原因，而铂/二氧化钛界面可重复的红氧反应对电阻切换行为起着重要作用。为了改变氧化物网络，降低二氧化钛中的氧含量，在四价钛离子的氧化物基质中加入三价Y离子。在Au/Tiy_xO_y/Pt结构中，Y_2O_3的加入显著地抑制了电阻开关电压的变化。

The chemical bonding features in TiO_2-based Resistance Random Access Memory (ReRAM) after resistance change have been studied to gain a better understanding of the mechanism of resistance switching. For the Pt/TiO_2/Pt structure after resistance switching, the oxidation of Pt electrode at low resistance state (LRS) and the reduction of this PtO_x at high resistance state (HRS) were observed by hard X-ray photoelectron spectroscopy. The result suggests that generation of oxygen vacancies in Ti-oxide matrix is responsible for the formation of conductive pass resulting in LRS and that repeatable red-ox reaction at the Pt/TiO_2 interface plays an important role on resistance switching behavior. To change in the oxide network and to reduce the oxygen content in TiO_2, tri-valent Y ions were added into the oxide matrix of quadri-valent Ti ions. In Au/TiY_xO_y/Pt structures it has been demonstrated that the variations in resistance switching voltages are markedly suppressed by the Y_2_O3 addition into TiO_2.