Cryo-FIB/SEM: Enhancing Precision and Minimizing Damage in Material Analysis

Cryogenic focused ion beam and scanning electron microscopy (cryo-FIB/SEM) is a technique used to reduce damage caused by ion and electron beams. When dealing with soft materials like polymers, biological specimens, battery materials, and others, room-temperature FIB milling and SEM imaging can cause deformation, melting, or amorphization. In cryo-FIB/SEM, the sample is cooled to cryogenic temperatures (-130°C) to prevent these issues. Liquid nitrogen is circulated through the CryoMat cold stage in our ThermoFisher FEI Helios G3 system for cooling. This method allows for precise FIB cross-sectioning and SEM imaging of beam-sensitive materials with minimal damages. Additionally, it facilitates the preparation of cryogenic TEM lamellae for cryo-TEM analysis.

Common applications for this technique include the examination of polymers, lithium battery materials, photoresist, and biological specimens, as well as the analysis of beam/heat-sensitive materials. One of its notable strengths lies in its ability to minimize artifacts associated with focused ion beam (FIB) milling processes, such as heating induced deformation, melting, bubbling, and intermetallic formation. Additionally, it enables the use of higher ion and electron beam currents and energies (operating voltages)  in comparison to conventional room-temperature FIB-SEM techniques.