AI 中文总结
该研究通过多种表征手段，揭示了超高真空下Si(111)上超薄3C-SiC的碳化与生长过程，为优化相关生长模板提供了时间分辨的实验依据。
AI 中文摘要
本研究在超高真空（UHV）条件下，通过乙烯暴露法探究Si(111)上碳化硅（SiC）的早期形成过程，以明确超薄层的时间依赖化学与形貌演化。将清洁Si(111)衬底在800℃下暴露于C₂H₄中2分钟至4小时，随后采用原位X射线光电子能谱（XPS）及非原位原子力显微镜（AFM）、扫描电子显微镜（SEM）、俄歇电子能谱（AES）、二次离子质谱（SIMS）和透射电子显微镜（TEM）对表面进行表征。Si 2p和C 1s峰分析显示，元素硅逐步转化为碳化Si-C相，SiC组分在120至160分钟间超过元素组分，180分钟后饱和至约80-81%，残留约19-20%的元素硅。SEM与AFM的关联分析揭示了同步的形貌演化，从稀疏孤立岛状物演变为合并的近连续层。AES深度剖析证实碳已掺入近表面区域，而非作为污染物弱吸附，据此将这些岛状物归为早期SiC晶核。TEM证实其为闪锌矿晶格，存在立方碳化硅（3C-SiC）。综上，这些结果提供了Si(111)上SiC成核、合并与层生长的时间分辨图像，与3C-SiC异质外延相关，可用于优化SiC/Si(111)模板，以在硅上生长III族氮化物及其他碳化物体系（如Mo₂C）。
英文摘要
The early-stage formation of silicon carbide (SiC) on Si(111) by ethylene exposure under ultra-high vacuum (UHV) was investigated to resolve the time-dependent chemical and morphological evolution of an ultrathin layer. Clean Si(111) substrates were exposed to C$_2$H$_4$ at 800 °C for 2 min to 4 h, and the surfaces followed by in-situ X-ray photoelectron spectroscopy (XPS) and ex-situ AFM, SEM, AES, SIMS and TEM. Si 2p and C 1s peak analysis shows the progressive conversion of elemental silicon into a carbidic Si-C phase, the SiC fraction overtaking the elemental component between 120 and 160 min and saturating near 80-81% beyond 180 min, leaving about 19-20% residual elemental silicon. Correlative SEM and AFM reveal a parallel morphological progression, from sparse isolated islands to a coalesced, near-continuous layer. AES depth profiling confirms carbon incorporated into the near-surface region rather than weakly adsorbed as contamination, assigning the islands to early SiC nuclei. TEM confirms the zinc-blende lattice and the presence of cubic silicon carbide (3C-SiC). Together, these results provide a time-resolved picture of SiC nucleation, coalescence and layer growth on Si(111), relevant to 3C-SiC heteroepitaxy, and can be utilized in the optimization of SiC/Si(111) templates for growth of III-nitride and other carbide systems on silicon (e.g. Mo$_2$C).
