A reproducible method for damage‐free site‐specific preparation of atom probe tips from interfaces

Abstract

Atom probe tomography (APT) is a mass spectrometry method with atomic-scale spatial resolution that can be used for the investigation of a wide range of materials. The main limiting factor with respect to the type of problems that can be addressed is the small volume investigated and the randomness of common sample preparation methods. With existing site-specific specimen preparation methods it is still challenging to rapidly and reproducibly produce large numbers of successful samples from specifically selected grain boundaries or interfaces for systematic studies. A new method utilizing both focused ion beam (FIB) and transmission electron microscopy (TEM) is presented that can be used to reproducibly produce damage-free atom probe samples with features of interest at any desired orientation with an accuracy of better than 50 nm from samples that require very little prior preparation.

Correlative Microscopy—Novel Methods and Their Applications to Explore 3D Chemistry and Structure of Nanoscale Lattice Defects: A Case Study in Superalloys

“…2d, it is marked and protected by in situ Pt deposition; see Fig. 2d-e. Figure 2f-k shows the step-by-step inplane lift-out 26,27 procedure schematically, where cut parts of the lift-out are positioned/attached on the electro-polished tips of a halved TEM Mo grid, which is held in a dedicated holder 8,28 and subsequently shaped into conical APT specimens by annular milling. 29 Figure 3a shows a bright-field TEM image of the APT specimen containing a C-type SF close to the [110] zone axis and in a g ¼ 00 2 À Á two-beam condition.…”

A Brief Overview of Atom Probe Tomography Research

“…Current studies are increasingly making use of a vast array of characterisation techniques, at multiple scales, with the view to correlate information from i.e. electron microscopy, optical spectroscopy or small-angle scattering (De Geuser et al, 2014;Felfer et al, 2012; Herbig et al., 2015; Kuzmina et al, 2015;Rigutti et al, 2013), and this is illustrated in Fig. 7.…”

“…The past decades have seen a rapid spread of scanning electron microscopes incorporating a focused-ion beam as a second source, often equipped with a gas-injection system that allows for localized chemical-vapor deposition of various metals (Pt, W) assisted by the secondary electrons emitted by the surface upon illumination by the electronor ion-beam, as well as a micromanipulator that consists in a needle that can be precisely moved inside the microscope chamber. Combining these different elements enables to liftout a small piece of the material, usually containing a specific region of interest, that can then be mounted onto a support grid or array of pre-sharpened posts, and finally shaped into one or several APT specimens (Felfer et al, 2012;Miller & Russell, 2006;Thompson et al, 2007). FIB-based specimen preparation therefore allows to select the region that is then to be analyzed, instead of blindly hoping to find it inside the specimen, and with an enhanced field-of-view, it is then possible to perform targeted APT analysis of a specific feature (e.g., phase, grain boundary, interface).…”

3D Atom Probe Tomography Study on Segregation of Yttrium in Modified Al-Si Alloys

“…A long bar was detached from the surface using the micromanipulator and transferred to prefabricated Si posts on a coupon, and small cut sections ($ 2 lm long) of the bar were welded on the Si posts. A procedure similar to that carried out in this research was described by Felfer et al 16 The samples mounted on the Si posts were annular milled to prepare taper-shaped needles with end radius of 20 nm to 40 nm. Under high vacuum and low temperature of 40 K, ions from the surface of this needle were evaporated inside the LEAP (Cameca 3000X HR).…”