Lift‐out procedures for atom probe tomography targeting nanoscale features in core‐shell nanowire heterostructures

Abstract

Focused ion beam (FIB) milling and lift‐out was used to prepare atom probe tomography (APT) specimens from GaN‐InGaN multi‐quantum well (MQW) nanowire arrays. Modifications to the conventional FIB lift‐out technique enable the site‐specific analysis of different regions of a single nanowire heterostructure. Three dimensional (3‐D) reconstructions of quantum wells generated by analysis along different directions with respect to the heterointerface demonstrate both the capabilities and limitations of atom probe tomographic analysis. The methods described herein can be applied to the site‐specific analysis of other complex 3‐D heterostructures. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events

“…Experiments were performed using FlexTAP. at 2 kV [12,13] . In this way, needle-shaped atom probe specimens with ∼50 nm radius at the apex and a cone angle of equal to 2.5 °w ere obtained.…”

Correlative investigation of Mg doping in GaN layers grown at different temperatures by atom probe tomography and off-axis electron holography

“…A lamella specimen and atom probe needle-shaped tips were prepared using a standard lift out procedure using a Scanning Electron Microscope/Focused Ion Beam (SEM/FIB) operated at 16 kV. 11,12 High-Angle Annular Dark Field Scanning Trasmission Electron Microscopy (HAADF-STEM) was performed using a double aberration corrected FEI Titan Ultimate operated at 300 kV. Figure 1(e).…”

Atom Probe Tomography Characterization of Dopant Distributions in Si FinFET: Challenges and Solutions

“…Final milling was carefully done to guarantee a fin correctly positioned in the tip, with Ga beam energy at 30 kV and current at 10 pA, as seen in Figure 2b. For the horizontal sampling direction, a home-made axial rotating manipulator (ARM) was utilized, similar to the literature design (Padalkar et al, 2014). Unlike a traditional lift-out lamella, the lift-out lamella had an irregular cross section designed for convenience in later axial rotating and transferring, as shown in Figure 2c.…”

“…However, the density correction is unable to rectify the trajectory overlaps of evaporated ions from different phases with different evaporation fields (Sha & Cerezo, 2005) and unable to overcome the uncertainty in the measurement of local compositions (Barnes et al, 2018). Alternatives are experimental approaches by changing the APT sampling direction (Padalkar et al, 2014; Martin et al, 2016; Kwak et al, 2017) or by completely removing the SiO 2 (Melkonyan et al, 2018) to minimize local magnification and trajectory aberrations.…”