Monte-Carlo simulation of focused ion beam lithography in inorganic resist

We have discussed the numerically calculated values such as ion range, ion concentration and ion transmission coefficient, and the defocused Ga+ ion-induced characteristics in inorganic resists. In this text, we present the results of Monte-Carlo simulation for FIBL in a-Se75Ge25 resist film which acts as a positive resist in ion beam lithography. This text contains the ion scattering trajectory of a delta function beam and the exposure and development results by a Gaussian beam. Carlo method is based on the simulation of individual particles through their successive collisions with resist atoms. For simulation, both the target depth (z-direction) and the lateral distance (x- or y-direction) are divided into discrete pixels (x:y:z=25:25:25[إ]) and, scattering and stop positions and ion loss energies are summed up in these individual pixels. The profiles of ion concentration and the spatial distribution of absorbed energy density for an incident ion beams with an Gaussian distribution are obtained by Fourier transformation of a delta function beam.