High-quality sample preparation for (scanning) transmission electron microscopy (S/TEM) can make the difference between impactful or mediocre analysis. An ideal lamella – the prepared cross-section of a sample – captures the right aspects of a feature of interest, balances signal intensity for structure and element analysis, and enhances the clarity of the end-image. Producing such a lamella requires great   care, precision, and consideration. Many people may not realize that there are numerous processes available to extract lamellae at different angles and orientations around a target feature of a sample; or that each orientation can expose slightly different information about the feature. To make the most of S/TEM measurements, analysts must prepare a lamella at the proper depth, angle, and thickness.

While the preparation process may be a bit intimidating, this webinar will show you: there is a lamella that can solve your problem! Covalent’s S/TEM sample expert, Ryan Dudschus, will walk you through the different lamella extraction methods. He’ll explain how different sample orientations allow you to access different cross-sections of features of interest and will guide you with case studies and examples on how to strategize the right extraction procedure based on your project’s needs.

This Webinar will Answer:

1. What are some preparation procedures used to access different lamella orientations?
2. What are strategies for bulking versus thinning a lamella?
3. How does the thinness of a lamella impact S/TEM data?
4. How should you strategize the right lamella preparation procedure?

What is the value of S/TEM Analysis?

Transmission electron microscopy (S/TEM) and its related methods are among the most powerful imaging techniques available. They generate atomic-resolution images that give engineers insight into structural features, defects and deformations, element and chemical composition / distribution, and even crystallographic phases on a sub-nanometer scale. This kind of detail yields far-reaching impacts, fueling vaccine synthesis in the pharmaceutical world and driving advancements to the microprocessors, integrated circuits, and semiconductor chips that run modern electronics. With recent advances in instrumentation, S/TEM analysis has never been more accessible and efficient, and the technique is seeing growing use in new areas of materials science and engineering.

Why does sample preparation matter?

In S/TEM analysis, the electron beam must fully pass through the sample before detection. As a result, lamellae that are too thick will have reduced image clarity due to limited signal transmission. On the other hand, lamellae that are too thin can lead to other imaging artifacts and will be increasingly susceptible to beam damage or damage during handling/transfer to the S/TEM microscope. Balancing these concerns, analysts must carefully remove material from the lamella until it achieves an ideal thickness between 20-80 nm (varied, depending on the sample).

Additionally, because S/TEM lamellae are extracted cross-sections (like 2D slices), it is common for lamellae to fail to enclose the full feature of interest; or for lamellae to contain the feature at unacceptable orientation angles. When this happens, regardless of how clear or high-quality the final images are, they may not provide the information or insight needed.