FIB-SEM Analysis

FIB-SEM Analysis

FIB-SEM Analysis Services

DigiM provides solutions across the whole suite of FIB-SEM analysis, from imaging collection to image segmentation and modeling. We pride ourselves on designing the best imaging protocol and conditions across industries and samples, from soft pharmaceutical polymers to hard rock core samples. At DigiM we work closely with our clients, using quantitative AI analysis to solve biggest R&D challenges. 

What is FIB-SEM?

Compared to conventional scanning electron microscopy (SEM) imaging, FIB-SEM 3D imaging experiment adds a “milling” tool in the form of a focused ion beam (FIB). Due to its heavy ionic mass, the Gallium FIB removes a small amount of material, thus exposing the surface and microstructures underneath. Repetitive FIB milling followed by SEM imaging produces a stack of images which can be reconstructed into a 3D volume. Our FIB-SEM imaging services go beyond just the images, with AI analysis to quantify the internal microstructures. 

FIB can remove a layer of material as thin as 3nm, allowing for an artifact-free cross sectioned surface to be prepared for SEM imaging. 

Left, a cross section of the polymer membrane of a drug pellet sample was prepared using conventional freeze cleave. Right, a cross-section was prepared through FIB milling. The microstructures revealed by the resulting cross-section SEM images are dramatically different. Due to mechanical fracturing, residual surface topology remains on the cleaved sample, and obscures the internal microstructure. In comparison, the FIB cross section reveals microporosity accurately, and allows for both qualitative and quantitative assessment.

Most importantly, FIB-SEM produces 3D volumes at a nanometer scale, which can be applied in image analysis and image-based simulation.

AI segmentation is used to classify the interior structures of a PLGA microsphere collected with 3D FIB-SEM. 

The AI segmentation, upon training, is applied to classify and quantify the entire network of particles and pores across the collected 3D FIB-SEM volume. 

Sample Representativeness

For microscopic imaging, sample representativeness is critical, yet often difficult to verify. FIB-SEM typically targets a resolution of 3–50 nm. Assuming an image produced has 2000×2000 pixels along X and Y directions, its field of view will be about 6 – 100 micrometers in size. This size is very small compared to other imaging techniques. Hence, it is critical to ensure that imaged volumes are representative. When using FIB-SEM microscopy, DigiM team works closely with our clients to guarantee that a representative sample volume will be imaged at the most appropriate resolution. Correlative imaging technique is often engaged by combining FIB-SEM with X-ray Microscopy, Plasma FIB-SEM, and Laser Cutting SEM.

Artifact Management

Regardless of how successful an imaging experiment is, there are always some imaging artifacts. FIB-SEM imaging can take a few hours to a few days. A sample with gas or liquid contents can react to electron and ion beams, which can cause undesirable effects such as sample drifting. Curtaining and charging are also not atypical. DigiM team manages mitigates the imaging artifacts during imaging experiments. Furthermore, a suite of software algorithms has been developed to correct artifacts, such as curtaining, stage drifting, and intensity variation. With a fundamental understandings on these artifacts for a specific material sample, they can be leveraged to design new experiments and study dynamic responses of such samples under electron and ion beam excitations.  

A few examples of DigiM’s artifact corrections are shown below.