PHYSICAL APPROXIMANTS TO ELECTRON-SCATTERING

In this paper, Monte Carlo modelling of electron scattering in a gener al composite substrate in the elastic regime is considered. In spite o f the great number of physical variables involved in the process, a si mplified formulation of the problem in terms of a limited number of di mensionless parameters is demonstrated by a modified application of Bu ckingham's theorem of Dimensional Analysis. A single generalised Bucki ngham argument is introduced and demonstrated to ultimately intervene in determining both forward and backscattering. This approach is exemp lified in the case of electron beam lithography, by evaluating the bac kscattering coefficient eta and the forward scattering width w. By int erpolation of the numerical data, simple Buckingham approximants to th e physical laws governing the process are finally derived, and they ar e applicable to all elemental and composite materials with e-beam volt ages from 5 to 150 kV and substrate thickness from 1 to 5000 nm. The u nique position of diamond as a substrate material in electron beam lit hography is emphasised.