Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM)
Transmission Electron Microscopy (TEM analysis) and Scanning Transmission Electron Microscopy (STEM) are similar techniques that image a sample using an electron beam. Image resolutions are around 1-2Å for TEM analysis and STEM. High energy electrons (80keV-200keV) are transmitted through electron transparent samples (~100nm thick). TEM and STEM have better spatial resolution than SEM but often require more complex sample preparation.
Though TEM and STEM are more time intensive than many other frequently used analytical tools, a variety of signals are accessible from these techniques making it possible to perform chemical analysis at the nano scale. Besides high image resolutions, it is possible to characterize crystallographic phase, crystallographic orientation (using electron diffraction experiments), generate elemental maps (by using EDS or EELS), and acquire images highlighting elemental contrast (Z-contrast or HAADF-STEM mode). These can all be accomplished from precisely located areas at the nm scale. STEM and TEM are excellent failure analysis tools for thin film and IC samples.