Charge Exchange Of Negative Ions Scattering On P-type Si Surfaces

This thesis presents the experimental study of charge exchange of negative ions(carbon, oxygen and fluorine) scattering on p-type Si Si(111) and Si(100) surfaces in the energy range from6.5to22.5keV. The charge states fractions of scattering particles were reported as function of incidence energy and angle. It is shown that:(1) In low energy range, charge exchange rely on incident ion energy and angle significantly:as incident ion energy increase, charge exchange chances decrease, proportion of negative ions increase, proportion of neutral particles reduce, number of positive ions increase slowly; To mirror scattering, chances of charge exchange is minimum, increase or reduce incidence angle relative to mirror scattering, chances of charge exchange increase gradually.(2) The bound energy of outer electrons in C-ions is smaller than that of O-and F-ion. So the additional electrons of negative ion and neutral particle is easy to lose.(3) Charge Exchange is easy to happen for scattering of ions on p-type Si (111) surface relative to p-type Si(100).