Dependence of Field Evaporation Voltage on Polarization Angle of Femtosecond Laser in 3D Atom Probe

Abstract

Recently, laser pulses on a three-dimensional atom probe have been used to induce field evaporation. The advantages of laser-pulse atom probes are application to higher resistivity materials such as semiconductors and high mass resolution. Early studies of laser-pulse atom probes were performed with laser pulses of nanosecond duration. All evidence from these early studies and most recent studies using sub-picosecond laser pulses have indicated that the field evaporation of atoms by laser pulses occurred by a thermal pulsing mechanism. On the other hand, some recent experiments with sub-picosecond laser pulses have resulted in the proposal of athermal mechanisms (e.g., optical rectification) of field evaporation. Thus, the mechanism of field evaporation at the apex of a needle specimen by sub-picosecond laser pulses has not yet been established. We report the dependence of field evaporation voltage on the polarization angle of femtosecond laser pulses for metal specimens.

Alternate field evaporation by changing laser pulsing and voltage pulsing dynamically for atom probe analysis

“…Voltage pulse which has been used from the establishment of AP in the 1960s is going to be replaced by short pulsed laser with high repetition rate in the nanometer scale characterization of materials by 3‐dimensional AP (3D‐AP) . The criterion for choosing appropriate trigger method is not clear and under discussion because it is difficult to compare the result of 2 triggering methods applied on the same sample in atomic scale . The precise comparison of 2 triggering methods was proposed by the authors by applying voltage pulse and laser pulse alternately to the identical sample .…”

“…1,2 The criterion for choosing appropriate trigger method is not clear and under discussion because it is difficult to compare the result of 2 triggering methods applied on the same sample in atomic scale. [3][4][5] The precise comparison of 2 triggering methods was proposed by the authors by applying voltage pulse and laser pulse alternately to the identical sample. 6 The results of mass spectrometric composition and spatial information of desorbed ions reflected the mechanism of triggering field evaporation.…”

Scanning Atom Probe Analysis Alternately Triggered by Voltage and Laser Pulse

“…Though the two triggering method could be explained by the same model dealing with the change of potential diagram under electric field and the vibration of the surface atom, the differences of analytical results such as the mass spectrum (charge state), shadowing effect, etc. are still under discussion [9][10][11].…”

Field Evaporation of Carbonaceous Materials in Laser-Assisted Atom Probe (Effects of the Laser Wavelength and Power)

“…We are currently developing a femtosecond pulsedlaser atom probe which aims for analyzing electronic devices [8,9]. Objective of this project is to establish the field evaporation mechanism to define the best evaporation conditions for the correct measurements [10]. In this study, the laser wavelength and power dependence of field evaporation of carbonaceous material has been observed.…”