Characterization of GeSi/Si Heteroepitaxial Layered Structures by Convergent Beam Electron Diffraction

Abstract

Both normal and off-axis convergent beam electron diffraction patterns (CBEDPs) have been applied to the characterization of GeSi epitaxial layer on Si substrate. The results show that CBED is an accurate method for the determination of the change in lattice parameters across the GeSi/Si interface. A CBED shadow imaging (CBSIM) technique has been introduced to detect, map and measure small crystal strains with an accuracy approaching that attainable using X-ray diffraction, but with far better spatial resolution. This allows the strain variation across the interface to be accurately determined. With the combination of normal CBEDPs, off-axis CBEDPs and CBSIMs, CBED has good feasibility for the strain characterization of layered structures.