Laser assisted field evaporation of oxides in atom probe analysis

We have investigated the laser assisted field evaporation phenomena of ZnO, and MgO to explore the feasibility of quantitative three dimensional atom probe analyses of insulating oxides. To assist the field evaporation of these oxides, the usage of short wavelength 343 nm ultraviolet (UV) laser was found to be more effective than 515 nm green laser. We observed field ion microscopy (FIM) image expansion and mass peak shifting when 343 nm laser was irradiated on MgO. This phenomenon can be attributed to the laser induced electron excitation which causes the reduction of the resistivity of the specimen.