Chalcogenide phase‐change materials (PCMs) exhibit distinct rapid changes in electrical properties upon repeatable switching between amorphous and crystalline structure and are thus attractive for emerging nonvolatile memory (phase‐change random access memory, PCRAM) applications. However, one of the key limitations of PCRAM concepts is their power consumption due to high RESET current requirement. In this work, the electrical memory switching behavior of Ge₂Sb₂Te₅ phase‐change thin films is investigated in detail. Bipolar electrical switching of PCMs at the nanoscale is demonstrated by use of conductive atomic force microscopy and visualized by simultaneously recording topography and electric current maps. The memory cell exhibits excellent scalability (≈15 nm lateral size), low RESET/SET operation voltages (0.5 V), and high on/off resistance ratios (≈5 × 10³) with a data storage density higher than 0.7 Tbit in.⁻². The physical switching mechanism of the memory is explored by investigation of the local conduction channel, evaluating the local microstructure and local chemical composition by advanced electron microscopy. The switching process is interpreted as a combination of both phase‐change and electrolytic mechanisms.

中文翻译：

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Ge2Sb2Te5相变材料薄膜的纳米级双极电开关

硫族化物相变材料（PCM）在非晶和晶体结构之间可重复切换时会显示出明显的电气特性快速变化，因此对于新兴的非易失性存储器（相变随机存取存储器，PCRAM）应用具有吸引力。但是，PCRAM概念的主要限制之一是由于高RESET电流要求而导致的功耗。在这项工作中，Ge ₂ Sb ₂ Te ₅的电存储切换行为详细研究了相变薄膜。通过使用导电原子力显微镜演示了PCM的纳米级双极电开关，并通过同时记录形貌和电流图来可视化。该存储单元具有出色的可扩展性（横向尺寸约为15 nm），低的RESET / SET操作电压（0.5 V）和高的开/关电阻比（≈5×10 ³），数据存储密度高于0.7 Tbit in。⁻²。通过研究局部传导通道，通过先进的电子显微镜评估局部微观结构和局部化学成分，探索了存储器的物理转换机制。开关过程被解释为相变和电解机制的结合。