One type of electron microscope is the scanning electron microscope (SEM) which produces images based on an electron beam that scans the surface of the sample using a raster scan pattern. Direct interaction of beam electrons with surface atoms of the sample reveal the surface topography, roughness, size and microstructure of the sample producing a black and white image. Accelerated electrons hit the sample surface thereby secondary electrons and backscattered electrons from the specimen are produced. While secondary electrons are commonly used for illustrating the morphology and topography of the samples, backscattered electrons give information on composition and multiphase contrast of samples. FIB-SEM (Focused Ion Beam – Scanning Electron Microscopy) is a coupled technique, which enables to image and modify (nano) samples. The FEI Strata Dual Beam contains two separated Columns. For imaging purposes, an electron beam is applied by high voltage (1-30 kV). The second column is a source of gallium ions, which can be used for sputtering large areas or focused patterns. A common application is the preparation of cross sections. To expose the sample to the ion beam, the stage has to be tilted by 52°.
Our machine is additionally equipped with a gas injection system (GIS) providing different reactive gases to deposit gold or platinum structures, or to selectively etch carbon structures. As an example, this can be utilized to write gold contacts or circuits on nano- or microscale. The machine is has a built-in loadlock system, enabling very fast introduction and exchange of samples, with a wide tolerance towards sample geometry.