Stable Metallic Enrichment in Conductive Filaments in TaOx-Based Resistive Switches Arising from Competing Diffusive Fluxes
Stable Metallic Enrichment in Conductive Filaments in TaOx-Based Resistive Switches Arising from Competing Diffusive Fluxes
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DOI：
10.1002/aelm.201800954
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发表时间：
2019-07-01
影响因子：
6.2
通讯作者：
Skowronski, Marek
中科院分区：
文献类型：
--
作者：
Ma, Yuanzhi;Goodwill, Jonathan M.;Skowronski, Marek
基于氧化物的连续开关器件为固态存储器技术带来了希望。信息编码通过在具有低电阻状态和高电阻状态（LRS/HRS）的两个非易失性状态之间电切换器件来实现。通常认为，这些状态之间的变化是由于氧空位的运动在电极之间形成连续（LRS）或有间隙（HRS）的细丝。由于细丝尺寸小，难以定位，因此很少直接评估细丝。电子显微镜实验揭示了TaO2.0 +/- 0.2基150 x 150 nm（2）器件的细丝结构和化学性质，形成后具有横截面几何形状，功耗低于1 mW。的细丝似乎是大致沙漏形的直径小于10 nm，并由富Ta和O-穷人的大部分是无定形材料与当地的组合物作为Ta丰富的TaO0.4。所形成的HRS具有高达10 nm宽的间隙，位于阳极旁边，由近化学计量的TaO2.5组成。钽和氧的分布与由温度梯度（Soret效应）和电场驱动的Ta和O两者的运动所形成的细丝一致。这种解释指向一种新的紧凑型连续开关器件。
Oxide-based resistive-switching devices hold promise for solid-state memory technology. Information encoding is accomplished by electrically switching the device between two nonvolatile states with low and high resistance states (LRS/HRS). It is generally accepted that the change between these states is due to the motion of oxygen vacancies forming a continuous (LRS) or gapped (HRS) filament between the electrodes. Direct assessments of filaments are rare due to their small size and the difficulty of locating the filament. Electron microscopy experiments reveal the filament structure and chemistry in TaO2.0 +/- 0.2-based 150 x 150 nm(2) devices with cross-sectional geometry after forming with power dissipation lower than 1 mW. The filaments appear to be roughly hourglass-shaped with a diameter of less than 10 nm and are composed of Ta-rich and O-poor mostly amorphous material with local compositions as Ta-rich as TaO0.4. The as-formed HRS has a gap up to 10 nm wide located next to the anode and composed of nearly stoichiometric TaO2.5. The tantalum and oxygen distribution is consistent with filaments formed by the motion of both Ta and O driven by temperature gradients (Soret effect) and an electric field. This interpretation points towards a new compact model of resistive-switching devices.