Applications and benefits of a Xe plasma FIB-SEM

FEI Company, Achtseweg Noord 5, 5651GG Eindhoven, the Netherlands

The combination of a focused ion beam (FIB) with a scanning electron microscope (SEM) in a FIB-SEM or DualBeam instrument provides a wide range of applications for material characterization. So-called FIB tomography [1,2] has enabled 3D imaging of structure, crystallography (via EBSD) and chemistry (by EDS) invaluable for a range of characterization applications. However the conventional gallium ion FIB also presents some limitations. First, there are many scenarios in materials science that require analysis across length scales up to many 100s of microns that lie beyond what a Ga ion FIB can typically access, relating to grain microtextures, grain neighborhoods, grain boundaries, inclusions and cracks. Second, gallium-based FIB at 30 keV induces a ~20 nm damage layer in crystalline samples that can hamper subsequent analysis.

In this paper we discuss the application of a DualBeam system equipped with a Xe Plasma beam FIB, the FEI Helios PFIB. This Xe+ beam provides higher currents and higher sputter yield (leading to a 20-50× throughput improvement) as well as significantly reduced material damage.

We demonstrate the performance of the PFIB through a large dimension (~100 µm) 3D tomography study of steel samples. The results show that PFIB tomography produces low levels of surface damage as evidenced by good channeling contrast as well as clear Kikuchi patterns from the machined surface.

Other ongoing experimental studies across a wide range of materials from paint to ceramics suggest the Xe PFIB can routinely, quickly and with high material quality provide 3D serial section tomograms over dimensions of many hundreds of microns. This not only expands the accessible length scales for FIB-SEM material characterization, it also means an improvement of the results compared to Ga FIB thanks to a remarkable surface finish quality.