金属掺杂改善HfO_(2)阻变存储器(RRAM)氧空位导电细丝性能

Influence of Metal Doping on Property of Oxygen Vacancy Conductive Filament in HfO_(2)

本研究采用金属掺杂的方式调控氧空位导电细丝的电子结构以获得更好的器件性能。计算了HfO_(2)体系中四组氧空位的形成能,得到V_(O4)-V_(O23)-V_(O34)-V_(O46)最易形成的氧空位簇;分波电荷态密度进一步表明在[010]晶向上电荷聚集形成导电通道。另外,研究了Ag、Mg、Ni、Cu、Al、Ta、Ti掺杂对该缺陷体系电子结构的影响,显示Ni与其它金属相比,在共缺陷体系中最易形成,体系最稳定;V_(O)-Ni共缺陷体系中导电细丝最均匀,最高等势面值最大,证明导电细丝最易形成;V_(O)-Ni之间相互作用能为-2.335eV,表明缺陷相互吸引;金属Ni具有很强的局域电子能力。

In order to improve performance of Resistive Random Access Memory(RRAM)based on HfO_(2),a method of metal doping was used to tailor electronic structure of oxygen vacancy(V_(o))conductive filaments(CF).The formation energy of four groups of V_(o) cluster was calculated based on the density functional theory.The results shows V_(O4)-V_(O23)-V_(O34)-V_(O46)-is the easily formed CF’s in[010]direction.On the other hand,the CF with different metal doping(Ag,Mg,Ni,Cu,Al,Ta or Ti)revealed that the formation energy is the lowest,the isosurface value is the highest and the CF is the most uniform in the case of Ni doping.The interaction energy between CF and Ni impurity was -2.335 eV,which indicated that the two defects attracting each other.The new impurity levels produced between the Valence Band and Fermi level indicates Ni has a strong local electron capacity.Overall,these findings provide some theoretical guidance for optimizing forming voltage and ON/OFF ratio of RRAM devices.