Simulation of LEIS spectra: use of a Monte Carlo code to calculate reionization

Low Energy Ion Scattering (LEIS) is a valuable tool for the characterization of thin film structures because it provides a unique way to measure both the elemental composition of the outer atomic layer and the subsurface elemental distribution (0-10nm). The two signals are distinguishable in LEIS spectra as surface peaks and subsurface tails respectively.
While the scattering processes that regulate surface peaks are well known, the charge transfer phenomena that influence the tail shape are still not fully comprehended. As a consequence, the correlation between tail shape and depth composition is still a challenge.
In this work, we study one of the charge transfer phenomena, the reionization, by comparing experiments and Monte Carlo simulations of scattering. The study is performed on bulk Si and on Si thin films deposited on transition metals.
We later show how the energy-dependent reionization probability of Si can be used to simulate LEIS spectra of samples with silicon as the top material. The simulations yield valuable insights into the in-depth composition of deposited structures. This is particularly useful for the study of multilayers because it enables the analysis of interfaces by static depth profiling.