Surface Structure Analysis in Ⅰ ) Low Energy Ion Scattering Ⅱ ) Medium Energy Ion Scattering 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

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

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

CAICISS apparatus 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.

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

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

Time of flight (ns) Intensity (counts) F/Ca = 1.0 ±0.2 Composition analysis by CAICISS of a monolayer of CaF 2 deposited on Si(111) Fig. 9

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

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

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

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

Ⅱ ) Medium Energy Ion Scattering Medium-energy CAICISS (ME-CAICISS) DUOPLASMATRON ION SOURCE X-Y STEERER EINZEL LENS ACCELERATION TUBE Q-LENS X-Y STEERER BENDING MAGNET COLLIMATOR CHOPPING ELECTRODE CHOPPING APERTURE POSCHENRIEDER ELECTROSTATIC DEFLECTOR MCP SCATTERED-ION DECELERATION TUBE SAMPLE AMPLIFIERCFD TIME ANALYZER PULSE GENERATOR DELAY (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 ゜ (a) (b) (c) (d) E 0 = 100 keV Subsurface and burried interface structure analysis by ME-CAICISS Fig. 15 Fig. 16

Sb (δ-doping) a-Si Si(001) Si T. Kobayashi et al., Appl. Phys. Lett. 74 (1999) Counts TOF (ns) ●■▲○□ △ (a) (b) Sb Si Normalized yield Polar angle (deg) Sb Si Fig. 17 (a) (b) (c) Concentration of Sb (%) Depth (nm) Fraction of substitutional Sb Original position of δ-doped Sb layer (d) Annealed at 750 o C Structure analysis by ME-CAICISS of a Si film with δ-doped Sb (after annealing at 750 o C) 25 nm