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.