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Unformatted text preview: I n C lass Presenta t ion: T ra nsm ission E lect ron M ic roscopy • Transmit electron beam through thin sample • Works like optical microscopy, similar to SEM • Column must be kept in vacuum (10-5 – 10-10 Torr) o Avoids scattering of electrons o Maintain thermal/chemical stability o Minimize contamination of sample • Very thin samples (<100 nm thick) • Sample Prep o <100 nm thick o <20 nm for good resolution o Carbon coating – keeps sample from being charged and won’t affect image too much o Thinning Mechanical • Planar (similar to grinding/polishing we did in lab) • Dimple – gives a thin area at center • Wedge (beveled plane) • For thin films, stack and glue films into tube and slice/thin Electrochemical • Used for metallic conductors • Jet polishing – etching • You know it’s done when you see the first hole • Ion milling – shoot inert gas ions to sputter away particles • Used after mechanical thinning • Imaging based on contrast from electron beam diffraction...
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- Spring '09
- Electrons, chromatic aberration, spherical aberration, Elastically scattered electrons