Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM)

Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) are related techniques that use an electron beam to image a sample. High energy electrons, incident on an ultra-thin samples allow for image resolutions that are on the order of 1 - 2 Angstroms. Compared to SEM, S/TEM has better spatial resolution, is capable of additional analytical measurements, and requires significantly more sample preparation.

Although more time consuming than many other common analytical tools, the wealth of information available from these experiments is impressive. Not only can you obtain outstanding image resolution, it is also possible to characterize crystallographic phase, crystallographic orientation (both by diffraction mode experiments), produce elemental maps (using EDS), and images that highlight elemental contrast (dark field mode)—all from nm sized areas that can be precisely located. STEM and TEM can be the ultimate failure analysis tools for thin film and IC samples.

Ideal Uses for S/TEM Analysis		Relevant Industries for S/TEM Analysis
Identification of nm sized defects on integrated circuits, including embedded particles and residues at the bottom of vias. Determination of crystallographic phases as a function of distance from an interface. Nanoparticle characterization: Core/shell investigations, agglomeration, effects of annealing… Catalyst support coverage. Ultra small area elemental maps. III-V super lattice characterization		Compound Semiconductors Intergrated circuit Magnetic media Nanomaterials MEMS Opto-electronics Semiconductors
Strengths of S/TEM Analysis		Limitations of S/TEM Analysis
The ultimate elemental mapping resolution of any analytical technique. Sub 0.5 nm image resolution. Small area crystallographic information		Significant sample preparation time Samples are often prepared that are <100nm Some materials not stable to electron beam