Control of Switching Modes and Conductance Quantization in Oxygen Engineered HfOx based Memristive Devices
Control of Switching Modes and Conductance Quantization in Oxygen Engineered HfOx based Memristive Devices
复制标题
DOI：
10.1002/adfm.201700432
复制
发表时间：
2017-08-25
影响因子：
19
通讯作者：
Alff, Lambert
中科院分区：
文献类型：
--
作者：
Sharath, Sankaramangalam Ulhas;Vogel, Stefan;Alff, Lambert
基于氧化铪 (HfOx) 的忆阻器件作为非易失性电阻随机存取存储器 (RRAM) 和神经形态电子学具有巨大潜力。尽管其两端结构看似简单，但快速增长的文献中报道的大量 RRAM 器件表现出相当复杂的电阻开关行为。使用 Pt/HfOx/TiN 基金属-绝缘体-金属结构作为模型系统，结果表明，良好控制的氧化学计量控制着灯丝的形成和多种开关模式的发生。人们发现，在电介质中导电丝的形成、破裂（复位）和重组（凝固）过程中，氧空位浓度是控制电场和焦耳热之间平衡的关键因素。此外，氧空位的工程稳定了原子尺寸的细丝收缩，在室温下设置和重置期间表现出整数和半整数电导量子化。识别不同开关模式和电导量化的材料条件有助于建立与 RRAM 材料的结构和功能特性相关的统一开关模型。在 HfOx 中设计氧化学计量的可能性将允许创建具有多个电导量子的量子点接触，作为多级忆阻量子器件的第一步。
Hafnium oxide (HfOx)-based memristive devices have tremendous potential as nonvolatile resistive random access memory (RRAM) and in neuromorphic electronics. Despite its seemingly simple two-terminal structure, a myriad of RRAM devices reported in the rapidly growing literature exhibit rather complex resistive switching behaviors. Using Pt/HfOx/TiN-based metal-insulator-metal structures as model systems, it is shown that a well-controlled oxygen stoichiometry governs the filament formation and the occurrence of multiple switching modes. The oxygen vacancy concentration is found to be the key factor in manipulating the balance between electric field and Joule heating during formation, rupture (reset), and reformation (set) of the conductive filaments in the dielectric. In addition, the engineering of oxygen vacancies stabilizes atomic size filament constrictions exhibiting integer and half-integer conductance quantization at room temperature during set and reset. Identifying the materials conditions of different switching modes and conductance quantization contributes to a unified switching model correlating structural and functional properties of RRAM materials. The possibility to engineer the oxygen stoichiometry in HfOx will allow creating quantum point contacts with multiple conductance quanta as a first step toward multilevel memristive quantum devices.