硅缓冲层提高选区外延生长硅基锗薄膜质量

Improved Quality of Selective Area Epitaxial Growth of Ge Film on Si Substrate by Inserting Si Buffer Layer

研究了Si缓冲层对选区外延Si基Ge薄膜的晶体质量的影响。利用超高真空化学气相沉积系统,结合低温Ge缓冲层和选区外延技术,通过插入Si缓冲层,在Si/SiO_2图形衬底上选择性外延生长Ge薄膜。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)表征了Ge薄膜的晶体质量和表面形貌。测试结果表明,选区外延Ge薄膜的晶体质量比无图形衬底外延得到薄膜的晶体质量要高;选区外延Ge薄膜前插入Si缓冲层得到Ge薄膜具有较低的XRD曲线半高宽以及表面粗糙度,位错密度低至5.9×10~5/cm^2,且薄膜经过高低温循环退火后,XRD曲线半高宽和位错密度进一步降低。通过插入Si缓冲层可提高选区外延Si基Ge薄膜的晶体质量,该技术有望应用于Si基光电集成。

The effect of Si buffer layer on the crystal quality of selective area epitaxy Ge film on Si substrate was studied. Combining with the low temperature Ge buffer layer and selective area epitaxy technology, by inserting Si buffer layer, Ge film on patterned Si/SiO2 substrate was grown selectively by using ultra-high vacuum chemical vapor deposition. By X-ray diffraction(XRD), scanning electron microscope(SEM)and atomic force microscope(AFM), the crystal quality and surface morphology of Ge film were characterized. The results show that the crystal quality of Ge film based on selective area epitaxy technology is better than that of the epitaxial film grown on no-patterned substrate. By inserting Si buffer layer before selective area epitaxy Ge film, the Ge film grown selectively owns lower full-width-at-half maximum of the XRD profile and lower surface roughness. And the dislocation density of the Ge film is low to 5.9×10^5/cm^2.Moreover, the full-width-at-half maximum of the XRD profile and dislocation density of Ge film were reduced after high-low temperature cycle annealing. In conclusion, by using inserting silicon buffer layer, the crystal quality of selective area epitaxy Ge film on Si can be improved,which will be a promising method for Si-based optoelectronic integration.