1. Scanning Electron Microscope
Michael Crocker
Valerie Goss
Rebecca Quardokus

2. Scale SEM Feature Sizes Viewing Nanomagnets
Down to 1 nm for best scopes
Maximum around 500,000x magnification
Viewing Nanomagnets
Feature Size: 5-10nm

3. Looking Smaller

4. Some light is “reflected”
Basic SEM Idea
Some light is “reflected”
Some is absorbed e-
Some are “reflected” e- e- e- e- e- e- e- e-
Some are absorbed e- e-

5. The Electron Beam Column
Beam created from heated filament
Beam travels through a vacuum
Electro-magnetic fields act as lenses
Electron beam hits the sample in a precise location
Scattered and “secondary” electrons are detected
Beam scans back and forth

6. The “Splash” Primary electrons come from the beam
Some electrons scatter back (BSE), and they move very fast
Other secondary electrons (SE) are dislodged and move more slowly

7. Water Hose and Splash

8. Be clear when using analogs!
Splash Analog
How it helps
E-Beam and Water Stream
Scattering and Splash
The beam moves back and forth (scan)
How it doesn’t help
Electron beam is created by magnetic field
The beam gets wider and thinner
The electrons penetrate the surface
Electrons can be selectively detected
Be clear when using analogs!

9. Other Analogs Solar System Mobile Sun and Planets on a Football Field
Onion as the shells of a Star
Solar System as an Atom
Etc.