State selective detection of sputtered Al neutrals by resonant laser ionization SNMS

It is important to optimize the resonance ionization efficiency of the sputtered particle by evaluating the internal energy of it. And also the dependence of the change of the internal energy of it on primary ion species and accelerating voltages was investigated. For this study, we developed proto-type resonance laser ionization SNMS instrument, which is a quadrupole SIMS apparatus combined with a wavelength tunable laser. The internal energy of the sputtered aluminum atoms, which has lowly lying excited state (112 cm⁻¹) on the ground state, was monitored. As the results, the internal energy of the sputtered aluminum atoms was not influenced by the change of the surface work function and primary ion beam energy at all. On the contrary, the density on lowly lying excited state drastically increased due to the existence of the oxygen on aluminum surface.