AI 中文总结
研究针对相变存储器中硫族化物合金存在的问题，提出用元素锗作为CMOS原生相变材料，在垂直PCM单元架构中，锗实现了快速结晶、优异热稳定性及低电阻漂移系数，可替代硫族化物材料并在标准半导体设施制造相变存储器。
AI 中文摘要
相变存储器（PCM）是一种用于快速、可扩展、非易失性数据存储的成熟技术，应用广泛。PCM主要依赖硫族化物合金，行业标准为Ge2Sb2Te5（GST）。但其中的Ge、Sb、Te原子在循环时会重新分布，导致随机操作和器件故障。有人提出用元素锑作为PCM材料，但它有亚稳态非晶态，影响数据保留。碲和锑还会污染CMOS生产线。本文介绍元素锗作为CMOS原生相变材料克服了这些问题。在垂直PCM单元架构中，锗实现了亚纳秒级结晶（240皮秒，比GST快40倍）、具有出色热稳定性的非易失性数据存储（10年高于110°C，GST约为87°C），且电阻漂移系数比GST低约60%。这些结果表明纯锗可替代硫族化物相变材料，能在标准半导体设施中制造相变存储器。
英文摘要
Phase-change memory (PCM) is a mature technology for fast, scalable, non-volatile data storage, with applications spanning embedded memory, as well as in-memory and neuromorphic computing. PCM predominantly relies on chalcogenide alloys, with $\mathrm{Ge_2Sb_2Te_5}$ (GST) as the industry standard. Yet in these alloys, the individual Ge, Sb, and Te atoms redistribute upon cycling, causing stochastic operation and ultimately device failure. To address this issue, elemental antimony was proposed as a PCM material, but it exhibits a metastable amorphous state that prevents reliable data retention. Moreover, tellurium and antimony can contaminate complementary metal-oxide-semiconductor (CMOS) production lines or act as unintended dopants, restricting manufacturing of PCM to dedicated fabs. Here we introduce elemental germanium (Ge) as a CMOS-native phase-change material that overcomes these fundamental limitations. In a vertical PCM cell architecture, Ge enables sub-nanosecond crystallization (240 ps, 40 times faster than GST), non-volatile data storage with excellent thermal stability ($>$110 °C for 10 years vs. $\sim$87 °C for GST), and a resistance drift coefficient approximately 60% lower than in GST. These results establish pure Ge, a standard semiconductor, as an alternative to chalcogenide phase-change materials, achieving superior performance in key metrics and enabling phase-change memory to be fabricated in standard semiconductor facilities.
