THEORETICAL SIMULATION OF BACKSCATTERED ELECTRON IMAGES OF SI SIXGE1-X STRUCTURES WITH A SCANNING ELECTRON-MICROSCOPE

In this work, we report on a theoretical study of the contrast formati on at Si/SixGe1-x interfaces in backscattered electron images of a sca nning electron microscope. The contrast at the heterointerface is calc ulated for different atomic concentrations (0 < x < 1) and energies (E 0 = 10 and 20 keV). The electron scattering phenomenon is simulated by employing a Monte Carlo method by using a single scattering approach. The signal intensity close to the interface shows a peak on the alloy side and a dip on the Si side. We explain this phenomenon by using th e diffusion theory of the backscattered electrons. The spatial resolut ion increases by decreasing the Si concentration in the alloy side and by decreasing the beam energy.