Monte Carlo simulations of nanometric structures: analysis of micromachined field emitters

A Monte Carlo program for the simulation of electron solid interaction of nanometric structures has been developed. The model uses either Mott cross section or a modified Rutherford cross section for calculating elastic scattering and the Bethe stopping power for calculating the inelastic scattering events. The X-ray production in a specimen is calculated by the Bethe and Gryzinski formulae. Validation of the model has been carried out by calculating the relative intensity (k ratio) of thin films to the bulk X-ray intensity. The simulation has further been applied to the case of microfabricated gated field emitters. A large Auger electron signal from the material situated up to several hundred nm from the position of the incident electrons is obtained. The magnitude of this signal could in certain cases equal to that obtained from pure elemental standards. These results should be taken into account while attempting to inspect structures involving sharp topographies.