Zhang Dong-Lan, Wang Jiong, Wu Qing, Du Yong
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
Information and Network Center, Central South University, Changsha, Hunan, 410083, China.
Phys Chem Chem Phys. 2023 Aug 23;25(33):22388-22400. doi: 10.1039/d3cp02050a.
Oxide-based resistive random access memory (RRAM) is standing out in both non-volatile memory and the emerging field of neuromorphic computing, with the consequence of increasing performance demands. Rare-earth doping is often used as an effective means for performance modulation. In this work, the modulation mechanism of the resistive switching (RS) behaviors in trivalent rare-earth Gd-doped HfO-based RRAM has been carefully investigated using first-principles calculations. The results of electronic structure analysis show that Gd doping would lead to a change in the local geometry of the m-HfO defect system and would enhance the Coulomb interaction between the atoms around Gd and oxygen vacancy (V), which may be one of the reasons for the enhanced conductivity of the HfO-based RRAM after Gd doping. Thermodynamic and kinetic study results indicate that there is a strong interaction between Gd and its surrounding V defects, and this strong interaction would not only attract more oxygen vacancies (V) to be generated near the dopant Gd, but also increase the migration energy barrier of the +2 charged V around the Gd doping site, thus suppressing the random generation of V filaments, which leads to a better uniformity of the switching parameters during the RS process and improves the performance stability of the devices. The results of this work will provide new insights into modulating the RS behaviors and improving the device performance of HfO-based RRAM through doping engineering.
基于氧化物的电阻式随机存取存储器（RRAM）在非易失性存储器和新兴的神经形态计算领域中脱颖而出，这导致了对性能要求的不断提高。稀土掺杂通常被用作性能调制的有效手段。在这项工作中，利用第一性原理计算仔细研究了三价稀土Gd掺杂的HfO基RRAM中电阻开关（RS）行为的调制机制。电子结构分析结果表明，Gd掺杂会导致m-HfO缺陷系统的局部几何结构发生变化，并会增强Gd周围原子与氧空位（V）之间的库仑相互作用，这可能是Gd掺杂后HfO基RRAM导电性增强的原因之一。热力学和动力学研究结果表明，Gd与其周围的V缺陷之间存在强烈的相互作用，这种强烈的相互作用不仅会吸引更多的氧空位（V）在掺杂剂Gd附近产生，还会增加Gd掺杂位点周围带+2电荷的V的迁移能垒，从而抑制V细丝的随机生成，这导致RS过程中开关参数具有更好的均匀性，并提高了器件的性能稳定性。这项工作的结果将为通过掺杂工程调制RS行为和提高HfO基RRAM的器件性能提供新的见解。
