Grazing-emission X-ray fluorescence as a multiprobe tool for thin-film metrology

Abstract

Recent research has demonstrated the high potential of grazing-emission X-ray fluorescence as a nanometrology tool for structures with complex 3D architecture. The technique now allows separate reconstruction of the spatial atomic distributions of different chemical elements both vertically and laterally, which opens up new and interesting applications in the nanofabrication industry. This study compares grazing-emission fluorescence with the well established grazing-incidence X-ray fluorescence method. The comparison uses a simple 1D thin-film structure. Reconstruction of the structure by both methods is performed and the statistical uncertainties of these reconstructions are compared by means of Monte Carlo Markov-chain simulations. For the forward model a semi-analytic approach is derived which allows simulation of the fluorescence intensity. This approach takes into account both grazing-incidence and grazing-emission cases. It also accounts for an even more complex physical phenomenon, the anomalous Kossel effect. Finally, using this semi-analytic approach, an experimental scheme combining grazing-incidence and grazing-emission X-ray fluorescence is studied theoretically.