Scanning Electron Microscopy (SEM)

SEM provides topographical and elemental information at magnifications of 10x to 100,000x with virtually unlimited depth of field.

Applications include

Materials evaluation

Failure analysis

Quality Control screening

Principle of Operation

A finely focused electron beam scanned across the surface of the sample generates secondary electrons, backscattered electrons, and characteristic X-rays. These signals are collected by detectors to form images of the sample displayed on a cathode ray tube screen. Features seen in the SEM image may then be immediately analyzed for elemental composition using EDS or WDS.

Secondary Electron Imaging shows the topography of surface features a few nm across. Films and stains as thin as 20 nm produce adequate-contrast images. Materials are viewed at useful magnifications up to 100,000x without the need for extensive sample preparation and without damaging the sample. Take a look at some fracture images.

Backscattered Electron Imaging shows the spatial distribution of elements or compounds within the top micron of the sample. Features as small as 10 nm are resolved and composition variations of as little as as 0.2% determined.