The determination of the thickness and composition of multilayered thin films in the SEM by x-ray microanalysis with Monte Carlo simulations

Abstract

X-Ray microanalysis is now a well established technique to determine the composition and the thickness of multilayer structures of different materials. The most popular software used to quantify such system are based on analytical φ(ρz) curves which are approximation of the x-Ray generation process. The computed φ(ρz) curves of multilayered samples are based on mixtures rules and weight functions which are not always accurate. In this paper, Monte Carlo simulations of electron trajectories in solids are used to compute φ(ρz) curves in multilayered specimens directly and then used to computed the K ratios.To validate this procedure, a TiN(100 nm)/Ti(10 nm) multilayer metallization structure deposited on SiO2(100 nm)/Si substrate was used in conjonction with a TiN(400 nm)/Si standard sample. This system is a very active field of research and development in the microelectronics industry. The thicknesses, composition and microstructure of both systems were fully characterized by Elastic Recoil Detection (ERD), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM).