超薄SGOI衬底上全局应变Si的制备和表征

Fabrication and characterization of global strained-Si on ultra-thin SGOI

应变Si是一种能在未来保持Si CMOS技术的发展继续遵循摩尔定律的新材料.本文结合SOI技术,利用改进型Ge浓缩技术制备了绝缘体上超薄的弛豫SiGe衬底,并使用超高真空化学气相沉积在较低温度下成功外延了厚度为25nm的应变Si单晶薄膜,扫描电子显微镜和原子力显微镜显示样品表面薄膜完整、平坦;高分辨透射电子显微镜和二次离子质谱表明:样品各层结构清晰、位错密度极低、界面陡直且元素分布均匀;紫外拉曼光谱证实了顶层Si中获得了1%的平面张应变,基于此的MOS器件有望获得比传统体Si大大提升的性能.

Strained Si is such a novel substrate near-fully relaxed Silicon-Germanium （SiGe） which can help keep Moore＇ s law in future years. Ultra-thin and substrate was fabricated using a modified Ge condensation technique, and then a 25nm thick biaxially tensile strained-Si with a low Root Mean Square （RMS） roughness was epitaxially deposited on the SiGe-On-Insulator （SGOI） substrate by Ultra High Vacuum Chemical Vapor Deposition （UHVCVD）. High-Resolution cross-sectional Transmission Electron Microscope （HR-XTEM） observations revealed that the strained-Si/SiGe layer was dislocation-free and the atoms at the interface were well aligned. Furthermore, Secondary Ion Mass Spectrometry （SIMS） results showed a sharp interface between layers and a uniform distribution of Ge in SiGe layer. One percent in-plane tensile strain in the strained-Si layer was confirmed by ultraviolet （UV）-Raman Spectra. According to those results, devices based on strained-Si are expected to have a better performance than the conventional ones.