Study of the field evaporation mechanism of laser-assisted atom probe

Abstract

The three-dimensional atom probe (3DAP) has been used to analyze atomic-scale characterization of a number of nanostructured materials. However, it faces a problem of uncertain field evaporation mechanism by using laser at this time. Resolving this problem is very important to carry out the quantitative analysis in 3DAP. In this paper, we focused on the different reflectivity of tungsten (50%), nickel (70%) and aluminum (85~90%), and measured them with changed laser power in the 3DAP. From the results, it was indicated that the shift of detection ions with the increase of laser power was different by the reflectivity of material. Also, we compared the field evaporation behavior at the laser pulse with that at the voltage pulse. According to these results, we verified the effect that affected the field evaporation mechanism due to the difference of reflectivity.

Influence of Tip Temperature on Field Evaporation in Atom Probe

“…Thus, the less charged ions might be more detected along with increase of laser power. This phenomenon was similar to results in 1064 nm laser and our previous study [9]. If the higher laser power generated stronger electric field, the more charged ions should be detected [2].…”

“…In our previous studies, we indicated the thermal effect on the field evaporation from the dependence of polarization angle of laser on field evaporation voltages [8] and the dependence of laser power on mass spectra and desorption images at the wavelength of 1064 nm [9].…”

“…In our laboratory, we have developed a wide-angle laserassisted 3DAP equipped with a femtosecond laser [6,7] and we have been studied the mechanism of field evaporation by the laser [8,9]. In our previous studies, we indicated the thermal effect on the field evaporation from the dependence of polarization angle of laser on field evaporation voltages [8] and the dependence of laser power on mass spectra and desorption images at the wavelength of 1064 nm [9].…”