Electron diffraction methods for the analysis of silicon carbide surfaces and the controlled growth of polytype heterostructures

摘要: The growth of different silicon carbide?(SiC) polytypes on each other is possible by control the surface structure and appropriate thermodynamic parameters. Special ultrahigh vacuum conditions, like those used in solid source molecular beam epitaxy, allow determination species also situ characterization growing polytype electron diffraction methods. reconstruction which favours a certain can be controlled reflection high energy diffraction. For non-destructive grown thin SiC film, methods x-ray photoelectron diffraction?(XPD) channelling used. interaction length electrons near 1?keV kinetic range 1?nm therefore sensitive to stacking sequence most common 3C, 4H, 6H with c-axis dimensions between 0.75 1.5?nm. To prepare heterostructures 4H/3C/4H or 6H/3C/6H, untwinned 3C films without double-positioning boundaries have grown. On-axis ?-SiC substrates uniform termination are prerequisite for this. Such surfaces prepared using temperature hydrogen etching, sublimation etching step-flow growth. These equally terminated crystals threefold symmetry particularly suitable detailed studies atomic-geometric their changes during after treatments. Results surface-sensitive scanning tunnelling microscopy, XPD low presented.