采用锗(Ge)浓缩技术对绝缘层上锗硅(SGOI)材料进行循环氧化、退火, 制备出19nm厚的绝缘层上锗(GOI)材料。然后对该GOI材料在400℃下进行O3氧化, 以进一步减薄GOI的厚度。采用高分辨透射电镜(HRTEM)、X射线反射(XRR)和原子力显微镜(AFM)等对样品形貌和结构进行表征。测试结果显示, O3氧化减薄后的GOI晶体质量得到提高, 且表面更加平整(厚度减薄2.5nm, 粗糙度RMS降低0.26nm)。通过循环的O3氧化减薄, 可获得高质量的超薄(小于10nm)GOI材料, 用于制备超薄高迁移率沟道Ge MOSFET。

Ultra-thin germanium-on-insulator(GOI) was fabricated by modified Ge condensation process of SiGe on SOI substrate. The prepared GOI was then oxidized in an atomic layer deposition chamber with O3 at 400℃ and the Ge oxides was removed with dilute hydrofluoric acid to get a thinner Ge layer. The GOI materials after O3 oxidation were characterized by HRTEM、XRR and AFM measurements, indicating better crystal quality and smoother surface than those of the as-prepared GOI by Ge condensation techniques. When the GOI was oxidized at 400℃ for 30min, the thinning thickness was about 2.5nm and the surface roughness was reduced from 1.23nm to 0.97nm. High crystal quality ultra-thin (below 10nm) GOI can be expected by cyclic O3 oxidation and thinning of Ge condensed GOI, which is one of the most promise candidates for high speed MOSFETs.