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This paper describes the use of a Monte Carlo model incorporating a finite-element method computing the electrostatic fields inside and outside a semiconductor, plus a ray-tracing algorithm for determining the doping contrast observed in a scanning electron microscope (SEM). This combined numerical method also enables the effects on the doping contrast of surface band-bending to be distinguished from those of external patch fields outside the specimen, as well as any applied macroscopic external fields from the detection system in the SEM. Good agreement of our new theory with experiment is obtained. The contrast characteristics in energy-filtered secondary electron images are also explained. The results of this work lead to a more advanced understanding of the doping contrast mechanisms, thereby enabling quantitative dopant profiling using the SEM. [ABSTRACT FROM AUTHOR]

We develop a spin-dependent injection model that can be used in time-dependent simulators of spintronic semiconductor devices. The physical basis of the method and the algorithm implementation are described. We test the validity of our model by simulating a two terminal ballistic semiconductor with the Monte Carlo technique and comparing the outcome to a simple low bias equivalent circuit, with excellent agreement. The results obtained demonstrate that the methodology proposed is suitable for use in time-dependent simulators of spintronic devices in order to make qualitative predictions. [ABSTRACT FROM AUTHOR]