GPU accelerated Monte-Carlo simulation of SEM images for metrology

Author(s):  
T. Verduin ◽  
S. R. Lokhorst ◽  
C. W. Hagen
Scanning ◽  
2012 ◽  
Vol 35 (2) ◽  
pp. 127-139 ◽  
Author(s):  
Y. G. Li ◽  
P. Zhang ◽  
Z. J. Ding

2005 ◽  
Vol 475-479 ◽  
pp. 4161-4164
Author(s):  
Z.J. Ding ◽  
H.M. Li ◽  
X. Sun

Topographic imaging of materials by a scanning electron microscope (SEM), using the secondary electrons and backscattered electrons escaped from the surface under a primary electron beam bombardment as image signals, has been a very important technique in application to material sciences and the related fields. In this work we have developed a new parallel Monte Carlo simulation program to calculate SEM images especially for an inhomogeneous sample with a complex structure, which may be constructed with some basic geometrical shapes containing different materials. The ray-tracing arithmetic is employed to obtain the corrected electron flight step length for electrons across the interface of different zones containing distinct elements. We have done simulations for several specimens with artificial structures at the nm level. The results illustrate some new characters of image contrast, demonstrating the applicability of this image simulation technique to the characterization of nano-scale structure.


2011 ◽  
Vol 364 ◽  
pp. 169-173
Author(s):  
Alsadat Rad Maryam ◽  
Kamarulazizi Ibrahim

This work reported the fabrication of nanopits array pattern using electron beam lithography (EBL). The effects of electron dosage on pattern shape were evaluated through EBL with a positive resist, Poly Methyl Meth Acrylate (PMMA), under acceleration voltages of 20 and 30 kV. Pattern of nanopits with 200 nm diameter have been created on PMMA to investigate the effect of various electron beam doses. The SEM images have shown effect of the voltage and dosage variation on them. In addition, Monte Carlo simulation has been done to show the scattering of electrons and proximity effect at different voltages in PMMA in order to explain the experimental results.


Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.


Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.


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