界面微结构对非晶氧化铪薄膜电致阻变效应的调控研究

Resistive random access memory (RRAM) has attracted great attention due to its promising potential for next generation data storage applications. However, as the field-induced formation and rupture of the nanoscale conductive filements (CF), which are responsible for the resisive switching behavior of oxide layers, are random and difficult to be controlled, a systematic and effective modulation of the cyclability and uniformity of the resistive switching properties of oxide RRAMs is still missing at present. It is reported that the formation of nanoscale CF is closely related to interfacial microtopography of the amorphous oxide films, therefore suggesting the possibility of controlling the nucleation and growth of the CF by designing interfacial microtopography of oxide thin films. In this project, we are aiming to tune the interfacial microtopography of the metal/amorphous HfOx thin film/metal vertical sandwiched or lateral structure and investigate the effect of raised electrode on flat substrate as well as concave structure of the media surface on the distribution of electric-field, formation of CF and resistive switching properties. With further understanding of the relationship between the resistive switching phenomena with spatially-localized charge transport, defect migration, interfacial charge and energy barrier, the switching mechanism of amorphous hafnium oxide film will be clarified to receive a stable HfOx-based RRAM, which may provide useful information, both therotically and experimentally, for the earlier commercialization of RRAM technology.

电阻型随机存储器（RRAM）具有高速、低功耗、存储单元尺寸小、与现有CMOS工艺兼容、可3D集成等的特点，是新一代存储技术的主要候选者。但由于氧化物阻变薄膜中导电丝的形成位置较难控制，导致电致阻变的稳定性很难得到系统有效的调控。研究发现，HfOx非晶膜中导电丝的形成与界面的微结构密切相关，因此可通过控制界面微结构来解决导电丝的生长难以控制的问题。在本项目中，我们拟通过调节金属/HfOx非晶膜/金属垂直三明治结构或平面叉指结构中的界面微结构，系统研究平面衬底上的微凸电极以及介质表面的内凹结构对非晶氧化铪薄膜中电场的分布、导电丝的形成以及电致阻变效应的调控规律，澄清电致阻变与空间限域的电荷输运、缺陷迁移、界面电荷、势垒及其分布的关联规律，阐明电致阻变效应的微观物理机制，获得具有稳定阻变性能的氧化铪基随机存储原型器件，为早日实现RRAM的产业化提供参考。

电阻型随机存储器（RRAM）因具有高速、低功耗、存储单元尺寸小、与现有CMOS工艺兼容、可3D集成等特点，是新一代存储技术的主要候选者。但由于氧化物阻变薄膜中导电丝的形成位置较难控制，导致电致阻变的稳定性很难得到系统有效地调控。本项目系统地研究了平面衬底上的微凸电极以及介质表面的内凹结构对非晶氧化铪（HfOx）薄膜中电场的分布、导电丝的形成以及电致阻变效应的调控规律，以及电致阻变与空间限域的电荷输运、缺陷迁移、界面电荷、势垒及其分布的关联规律，证明了HfOx非晶膜中导电丝的形成与界面的微结构密切相关，且可通过控制界面微结构来解决导电丝的形核和生长难以控制的问题，提高器件的稳定性和抗疲劳性。最终通过设计界面结构，获得了4种性能良好的原型器件，包括ITO/HfOx/ITO、Au/HKUST-1/Au、Pt/ZnO/Cu和Pt/ferritin/Pt，可为早日实现RRAM的产业化提供参考。