Monte Carlo Simulations of Edge Artefacts in MULSAM Images

Abstract

A fast Monte Carlo model for the simulation of electron-solid interactions in small dimensional systems such as raised and buried structures and thin multilayer films is reported. It is based on single scattering and uses a modified Rutherford scattering cross-section. The model is used to develop a new method for the detection and correction of edge enhancement encountered in high resolution Auger imaging of topographical structures and is applied to the case of a 1.4 µm thick aluminum overlayer on a silicon substrate. Secondary, backscattered, Auger and low energy loss electrons and characteristic x-rays are produced. These are simulated for collection in an array of detectors around the azimuth. In this method the low energy loss electrons are used to detect the edge position while backscattered electrons of energies ≥ 0.75 of the incident electron beam energy are used for the correction of the Auger edge enhancement. The correction of the substrate enhancement from a bevelled multilayered sample made of 12 alternating 10nm thick films of cobalt and platinum on a silicon substrate is also reported. Use here is made of the relationship of the sample current with the backscattering coefficient for the correction of the substrate backscattering effects.