Coherent Bremsstrahlung effect observed during STEM analysis of dopant distribution in silicon devices using large area silicon drift EDX detectors and high brightness electron source

摘要: In this paper, during dopant analysis of silicon devices, we have observed a phenomenon generally neglected in EDX analysis: the coherent Bremsstrahlung (CB). We discussed reason why and came to conclusion that analytical TEM used for these experiments presents configuration performances, which makes equipment very sensitive CB effect. This is due large collection solid angle high counting rate four drift detectors (SDD), brightness electron source providing probe current moreover geometry favorable on axis crystal observations. analyzed devices containing Si [110] [100] areas at different energies (80-120-200keV). also relaxed SiGe (27 40at% Ge). The effect, whose intensity maximum near zone beam alignment, manifests as characteristic broad peaks present X-ray spectrum background. peak are predicted by simple formula deduced models found literature simply. evaluate intensities discuss importance effect detection quantification traces impurities. give information structure (measurement periodicity along axis) allow, every particular experiment or system, determine median take off detectors.