Kikuchi-Band Analysis of X-Ray Photoelectron Diffraction Fine Structure of Si(100) by Precise Angle-Resolved X-Ray Photoelectron Spectroscopy

X-ray photoelectron diffraction fine structure of Si(100) is studied with precise angle-resolved X-ray photoelectron spectroscopy. Polar-angle intensity distributions of the Si 2p photoelectron emission excited by Al Kα X-rays are measured from H-terminated Si(100) along some azimuthal angles, and are qualitatively interpreted using both forward-focusing peaks along zone axes and Kikuchi bands associated with planes of low indices ({220}, {400}, {111} and {311}). To confirm the interpretation experimentally, we prepare ultrathin Si(100) layers on SiO2 from silicon-on-insulator (SOI) wafers. The thicknesses of the ultrathin Si(100) layers are adjusted so that the SOI layer is thick enough to exhibit the forward-focusing peak along [100] but slightly thinner than the thickness in which the contribution of the Kikuchi pattern weakens. It is observed experimentally, for the first time, that the intensities of X-ray photoelectron diffraction fine structure due to Kikuchi lines decreases for such ultrathin Si(100), while the forward-focusing peak remains unchanged, as expected from our interpretation.