Abstract
Here we describe the first automated fully integrated in-microscope broad ion beam (BIB) system. Ar+-BIB has several advantages over Ga+ focused ion beam (FIB) and Xe+ plasma-FIB (PFIB) methods inducing less beam damage, especially for ion beam sensitive materials. It can mill areas several orders of magnitude larger (up to millimetre scale), and is not confined to the edge of the sample with associated curtaining issues. BIB is shown to have sputter rates up to five times higher than comparable FIB techniques. This new coupled BIB–SEM system (commercial name ‘iPrep™II’) enables in-microscope surface polishing to remove contaminants or damage for two dimensional (2D) imaging, as well as automated serial section tomography (SST) by milling and imaging hundreds of slices, cost and time efficiently. The milled slice thickness can be controlled from a few nanometers up to a micrometre. A novel sample transfer, handling and interlock system allows automated and sequential BIB polishing, scanning electron microscopy (SEM) and analysis by secondary electron (SE) imaging, electron back scatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) for 3D microstructure analysis. Furthermore, insulating surfaces can be sputter coated after milling each slice to reduce charging during SEM analysis. The performance of the instrument is demonstrated through a series of case studies across the materials, earth and life sciences exploiting the imaging, crystallographic and chemical mapping capabilities. These include the study of butterfly defects in bearing steels, meta-stable intermetallic phases in bronze bearings, shale gas rock, aluminium plasma electrolytic oxide (PEO) coatings as well as liver and mouse brain tissues.
Highlights
Methods of 3D imaging within the scanning electron microscope are attracting increasing interest [1]
The broad ion beam (BIB) can polish very large areas, but in-order to focus on specific features of interest more time effectively, several smaller sites of interest can be specified for high spatial resolution electron back scatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) mapping, rather than acquire information across the whole milled area
Step 1: the robotic arm transfers the sample holder to the Ar+ BIB chamber where the sample is milled for a user-defined period or dose, glancing angle or gun tilt that ranges from 0° to 18° from the sample surface that is equivalent to angle of incidence (AoI) range from 90° to 72° and accelerating voltage (100 eV–8 kV) with a full recipe capability through which the user can program a series of milling energies and times
Summary
Methods of 3D imaging within the scanning electron microscope are attracting increasing interest [1]. This paper outlines the first coupled and fully integrated Broad Ion Beam–Scanning Electron Microscope (BIB–SEM) [2,3] It allows automated sequential imaging and milling without user intervention or exposure of the sample to air. The BIB can polish very large areas (millimetres in dimensions), but in-order to focus on specific features of interest more time effectively, several smaller sites of interest can be specified for high spatial resolution EBSD and EDS mapping, rather than acquire information across the whole milled area The versatility of such analysis strategies is useful in optimising the data acquisition process in a data and time efficient manner according to the application. The capabilities of the coupled BIB–SEM system are demonstrated and discussed through a wide-ranging series of case studies from the materials, earth and life sciences
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
