Scanning Electron Microscopy
and
Scanning Auger Microscopy

Secondary Electron Microscopy (SEM)
(click on Thumbnail for larger SEM image.)

The 10 Kev sub-micron gun, from Kratos Analytical, produces a magnified image of the specimen by scanning a finely focussed beam of up to 10 KeV electrons across the specimen surface. Secondary electrons generated in the specimen by this beam are detected by a secondary electron multiplier and amplified. The signal is used to modulate a cathode ray tube, whose raster is in synch with the electron beam scan, resulting in an image on the screen. The image is a three dimensional plot of secondary electron intensity versus an X and a Y coordinate.

By decreasing the raster size, the electron beam will analyze a smaller area resulting in a higher magnification. By decreasing the electron beam spot size better resolution can be obtianed. Kratos reports the beam size to be approximately 1000 angstroms at 5 KeV, This corresponds to roughly 500 angstroms at 10 KeV (exact numbers are not known but will be reported when they become available).

Auger Electron Microscopy (AEM)
(Click on Thumbnial to see larger Auger Map.)

By analysing electrons of a specific kinetic energy which is equivalent to the kinetic energy of an Auger electron from an element which is believed to be on the surface of a sample, and subtracting the background, or secondary electron, intensity an spacial map of any element can be obtained. The ultimate resolution of the instrument is currently being tested and improved. Results showing the latest images will be displayed below and updated as better resolutions are obtained. Currently features on the order of 1 micron are being resolved regularly. With some minor improvements it is hoped that we can improve the resolution by an order of magnitude.