Computer simulation of high-resolution transmission electron microscope images based on ball-and-spoke models of (100) Si/SiO2 interface

Cross-sectional high-resolution transmission electron microscope (HRTEM) images of the (100) Si/SiO2 interface have been computer simulated on the basis of various interface models in order to facilitate the interpretation of experimental HRTEM images. Continuous random networks of SiO2 have been constructed on crystalline Si substrates with different surface morphologies using plastic balls and spokes. The distortion energy introduced by artifacts in the model has been relaxed by modifying the atom positions. HRTEM images of the models have been calculated using the multislice dynamical electron scattering method. Although models with pyramidlike or edgelike protuberances delineated by {111} facets on the (100) interface give HRTEM lattice images close to the observed ones, the undulation in the calculated images is always smaller than that in the actual atomic arrangement. A rough (100) interface with a suboxide region is an alternative to the energetically favorable interface structure which gives a very flat calculated image.