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Surface Structure Analysis

Surface Structure Analysis. Simultaneous Determination of Atomic Arrangement (not only surface atoms but also shallow subsurface atoms) and Elemental Species of Atoms by Specialized form of Ion Scattering Spectroscopy. in Ⅰ) Low Energy Ion Scattering

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Surface Structure Analysis

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  1. Surface Structure Analysis Simultaneous Determination of Atomic Arrangement (not only surface atoms but also shallow subsurface atoms) and Elemental Species of Atoms by Specialized form of Ion Scattering Spectroscopy in Ⅰ) Low Energy Ion Scattering Ⅱ) Medium Energy Ion Scattering

  2. Ⅰ) Low Energy Ion Scattering The first idea of Impact Collision Ion Scattering Spectroscopy (ICISS) M. Aono et al., Jpn. J. Appl. Phys. 20 (1981) L829. Experimental scattering angle θLis taken close to 180° for quantitative structure analysis Fig. 1

  3. Extension of ICISS to more convenient Co-axial ICISS(CAICISS) Experimental scattering angle θLis taken just at 180° for more convenient quantitative structure analysis Fig. 2

  4. CAICISSapparatus commercialized by Shimadzu Corp. CAICISS - I Fig. 4 Fig. 3 CAICISS-I was selected in top-ten Japanese industrial productions in 1991 by the Nikkan-kogyo Newspaper.

  5. Power of CAICISS 1) Energy-distribution (spectrum) of scattered ions Elemental analysis of all atoms 2) Angular Dependence of scattered ion intensity Quantitative atomic arrangement analysis Fig. 5 Fig. 6 Fig. 7 3) Time dependence of spectrum of scattered ions Time-resolved observation of dynamic processes

  6. Method of elemental analysis of surfaces atoms by ion scattering ( in case of CAICISS, θL=180°) b a Fig. 8

  7. Composition analysis by CAICISS of a monolayer of CaF2 deposited on Si(111) F/Ca = 1.0 ±0.2 Intensity (counts) Time of flight (ns) Fig. 9

  8. Method to determine the shape of shadow cone experimentally by CAICISS L b a Method to determine the position of atom B relative to the position of atom A by CAICISS Intensity of ions scattered from atom B A B a b Fig. 10 Fig. 11

  9. Structure analysis of TiC(111) surface by CAICISS Fig. 12

  10. Structure analysis of CaF/Si(111) by CAICISS (a) Intensity of ions scattered from Ca atoms Angle (b) F d Ca Si 0.064±0.005 nm (0.079 nm in bulk) Fig. 13

  11. Structure analysis of Si(111)√3x √3-Ag surface by CAICISS Fig. 14

  12. Ⅱ) Medium Energy Ion Scattering Medium-energy CAICISS (ME-CAICISS) E0= 100 keV (a) Ion beam source in combination with a 100 keV accelerator (b) Beam chopping system (c) Target on a 3-axis goniometer (d) TOF energy analyzer located at a scattering angle of 180 ゜ POSCHENRIEDER ELECTROSTATIC ACCELERATION DEFLECTOR COLLIMATOR X-Y STEERER TUBE CHOPPING BENDING ELECTRODE MAGNET Q-LENS EINZEL LENS CHOPPING (a) APERTURE X-Y (b) PULSE STEERER GENERATOR (d) DUOPLASMATRON (c) ION SOURCE MCP SAMPLE SCATTERED-ION DECELERATION TUBE DELAY TIME ANALYZER AMPLIFIER CFD DELAY Subsurface and burried interface structure analysis by ME-CAICISS Fig. 15 Fig. 16

  13. Structure analysis by ME-CAICISS of a Si film with δ-doped Sb (after annealing at 750oC) 250 ● ■ ▲ ○ □ △ 200 a-Si Si Si(001) (a) (b) 150 Counts (b) 100 Sb Si 50 (a) 25 nm 0 Sb (δ-doping) 400 440 480 520 TOF (ns) Annealed at 750 oC (c) 1.2 Sb 1.0 Original position of δ-doped Sb layer (d) 0.8 0.6 0.4 1.0 0.2 1.2 0.0 Normalized yield 0.8 Si 1.0 <015> <013> 0.6 0.8 <012> <001> <017> <014> Concentration of Sb (%) Fraction of substitutional Sb 0.6 0.4 0.4 0.2 0.2 5 0.0 0 5 10 15 20 25 0.0 4 Polar angle (deg) 0 5 10 15 20 25 30 Depth (nm) 3 T. Kobayashi et al., Appl. Phys. Lett. 74 (1999) 673 2 1 Fig. 17 0

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