Goux Ludovic, Radhakrishnan Janaki, Belmonte Attilio, Witters Thomas, Devulder Wouter, Redolfi Augusto, Kundu Shreya, Houssa Michel, Kar Gouri Sankar
IMEC, Leuven, Belgium.
Faraday Discuss. 2019 Feb 18;213(0):67-85. doi: 10.1039/c8fd00115d.
This study is focused on Conductive Bridging Random Access Memory (CBRAM) devices based on chalcogenide electrolyte and Cu-supply materials, and aims at identifying the key material parameters controlling memory properties. The CBRAM devices investigated are integrated on CMOS select transistors, and are constituted by either Ge-Se or Ge-Te electrolyte layers of various compositions combined with a Cu2GeTe3 active chalcogenide electrode. By means of extensive physical and electrical characterization, we show for a given electrolyte system that slower write is obtained for a denser electrolyte layer, which is directly correlated with a lower atomic percentage of the chalcogen element in the layer. We also evidence that the use of Ge-Se electrolyte results in larger write energy (voltage and time), however with improved state retention properties than for Ge-Te electrolyte materials. We associate these results with the stronger chemical bonding of Cu with Se, resulting both in a stabilized Cu filament and a slower Cu cation motion. More robust processing thermal stability is also observed for Ge-Se compared to Ge-Te compounds, allowing more flexibility in the integration flow design.
本研究聚焦于基于硫族化物电解质和铜供应材料的导电桥接随机存取存储器（CBRAM）器件，旨在确定控制存储器特性的关键材料参数。所研究的CBRAM器件集成在CMOS选择晶体管上，由各种成分的Ge-Se或Ge-Te电解质层与Cu2GeTe3活性硫族化物电极组成。通过广泛的物理和电学表征，我们表明，对于给定的电解质系统，较致密的电解质层写入速度较慢，这与该层中硫族元素较低的原子百分比直接相关。我们还证明，使用Ge-Se电解质会导致更大的写入能量（电压和时间），不过与Ge-Te电解质材料相比，其状态保持特性有所改善。我们将这些结果与Cu与Se更强的化学键联系起来，这既导致了稳定的Cu细丝，也导致了较慢的Cu阳离子运动。与Ge-Te化合物相比，Ge-Se还表现出更强的加工热稳定性，这使得在集成流程设计中具有更大的灵活性。
