Abstract A new simultaneous acquisition software for Precession Electron Diffraction (PED) and Energy Dispersive X-ray Spectroscopy (EDX) mapping has been developed. This approach has been used to study the RESET operation in Ge-rich Ge-Sb-Te (Ge-rich GST) non-volatile Phase-Change Memory (PCM). Such an operation consists in the local amorphization of the device's active volume, which defines the memory state. Using PED patterns indexing, we were able to segment the amorphous area, and access its composition through EDX quantification. Moreover, both the spatial distribution and the chemical composition of the two crystalline phases overlapped in the chalcogenide layer were retrieved by using the spectral unmixing approach and PED patterns indexing. It evidences that Ge and Ge2Sb1Te2 (GST-212) crystals are separated in the studied devices. Despite this, we show that Ge-enrichment is preserved in the active volume of a functional device, which is crucial to guarantee the RESET state stability at high temperature. We also link the origin of the failure of the RESET operation observed in a dysfunctional device to the larger Ge-depleted area.

中文翻译：

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通过耦合扫描进动电子衍射和能量色散 X 射线分析研究相变存储器件

摘要 开发了一种新的用于旋进电子衍射 (PED) 和能量色散 X 射线光谱 (EDX) 映射的同步采集软件。这种方法已用于研究富锗 Ge-Sb-Te（富锗 GST）非易失性相变存储器 (PCM) 中的 RESET 操作。这种操作包括设备活动卷的局部非晶化，它定义了内存状态。使用 PED 模式索引，我们能够分割无定形区域，并通过 EDX 量化访问其组成。此外，通过使用光谱分离方法和 PED 模式索引，可以检索硫族化物层中重叠的两个结晶相的空间分布和化学成分。这证明 Ge 和 Ge2Sb1Te2 (GST-212) 晶体在所研究的器件中是分离的。尽管如此，我们表明在功能器件的活性体积中保留了 Ge 富集，这对于保证高温下的 RESET 状态稳定性至关重要。我们还将在功能失调的设备中观察到的 RESET 操作失败的根源与更大的贫锗区域联系起来。