Simulation Study On X-ray Photoemission Electron Microscopy Image For Ag Au/Si Structure

The third generation of X-ray photoemission microscope with the synchrotron ra-diation source is widely applied in the investigation of surface,inter-surface,films,nano-structures and magnetic materials and so on (1st chapter). According to the theoriesof X-ray-solid interaction and electron-solid interaction, by using Monte Carlo method(2st chapter), the images of X-ray photoemission electron microscope are investigatedunder different incident conditions and for different surfaces (3st chapter) . The pro-posal about future work is given in 4st chapter.Photoelectrons are generated in solid during the X-ray-solid interaction. Simul-taneously, the core holes are produced, which will lead to the production of Augerelectrons and X-ray ?uorescence. The secondary electrons are generated in the cas-cade process due to photoelectrons and Auger electrons scattering. In our simulation,the photo-ionization cross section is employed to describe the photoelectron excita-tion, and in the subsequent process of electron-solid interaction, the Mott cross sectionand dielectric function method are used to describe the electrons elastic scattering andinelastic scattering respectively. The complex surface geometry was constructed byconstructive solid geometry (CSG) method. The intersections of electron trajectorywith the basic geometries are calculated by using the ray-tracing method in graphics.In this work, we simulated the image of XPEEM with different incident anglesand photon energies, and image for nano structure of different material, different sur-face and different dimension in the same incident condition. There are two modes inXPEEM: total electron yield (TEY) and partial electron yield (PEY). According to thesimulation results, it is obvious that the brightness of image increases with the inci-dent angle and the height of the dots increasing due to the effective distance to producephotoelectrons and the opportunity to escape from the surface for electrons increasing.For balls, the electrons can escape from the top more easily than from the boundaryso that the boundary presents brighter, which was observed in experiments. The imagefor small size dots is different to that for dots with big radius. The edge of small dot isintensified. The XPEEM images for Ag and Au were simulated respectively. Becauseof the difference of photo-ionization cross section and the yield of secondary electrons,the images for the two elements were quite different. Because both the photo-ionizationcross section and yield of secondary electrons of gold are larger than those of silver, the image of Au dot is brighter than that of Ag dot obviously.