In modern physics we are interested in systems with many degrees of freedom. The Monte Carlo (MC) method gives us a very accurate way to calculate definite integrals of high dimension: it evaluates the integrand at a random sampling of abscissa. MC is also used for evaluating the many physical quantities necessary to the study of the interactions of particle-beams with solid targets. Letting the particles carry out an artificial random walk and taking into account the effect of the single collisions, it is possible to accurately evaluate the diffusion process. Secondary electron emission is a process where primary incident electrons impinging on a surface induce the emission of secondary electrons. The number of secondary electrons emitted divided by the number of the incident electrons is the so-called secondary electron emission yield. The secondary electron emission yield is conventionally measured as the integral of the secondary electron energy distribution in the emitted electron energy range from 0 to 50eV. The problem of the determination of secondary electron emission from solids irradiated by a particle beam is of crucial importance, especially in connection with the analytical techniques that utilize secondary electrons to investigate chemical and compositional properties of solids in the near surface layers. Secondary electrons are used for imaging in scanning electron microscopes, with applications ranging from secondary electron doping contrast in p-n junctions, line-width measurement in critical-dimension scanning electron microscopy, to the study of biological samples. In this work, the main mechanisms of scattering and energy loss of electrons scattered in dielectric materials are briefly treated. The present MC scheme takes into account all the single energy losses suffered by each electron in the secondary electron cascade, and is rather accurate for the calculation of the secondary electron yield and energy distribution as well.
Monte Carlo Simulation of Secondary Electron Emission from Dielectric Targets
Dapor, Maurizio
2012-01-01
Abstract
In modern physics we are interested in systems with many degrees of freedom. The Monte Carlo (MC) method gives us a very accurate way to calculate definite integrals of high dimension: it evaluates the integrand at a random sampling of abscissa. MC is also used for evaluating the many physical quantities necessary to the study of the interactions of particle-beams with solid targets. Letting the particles carry out an artificial random walk and taking into account the effect of the single collisions, it is possible to accurately evaluate the diffusion process. Secondary electron emission is a process where primary incident electrons impinging on a surface induce the emission of secondary electrons. The number of secondary electrons emitted divided by the number of the incident electrons is the so-called secondary electron emission yield. The secondary electron emission yield is conventionally measured as the integral of the secondary electron energy distribution in the emitted electron energy range from 0 to 50eV. The problem of the determination of secondary electron emission from solids irradiated by a particle beam is of crucial importance, especially in connection with the analytical techniques that utilize secondary electrons to investigate chemical and compositional properties of solids in the near surface layers. Secondary electrons are used for imaging in scanning electron microscopes, with applications ranging from secondary electron doping contrast in p-n junctions, line-width measurement in critical-dimension scanning electron microscopy, to the study of biological samples. In this work, the main mechanisms of scattering and energy loss of electrons scattered in dielectric materials are briefly treated. The present MC scheme takes into account all the single energy losses suffered by each electron in the secondary electron cascade, and is rather accurate for the calculation of the secondary electron yield and energy distribution as well.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione
