Non-destructive depth profile evaluation of multi-layer thin film stack using simultaneous analysis of data from multiple X-ray photoelectron spectroscopy instruments

Abstract

Non-destructive depth profile evaluation of multi-layer thin film stacks using simultaneous analysis of angle-resolved X-ray photoelectron spectroscopy data from multiple instruments is demonstrated. The data analysis algorithm, called the maximum smoothness method, was originally designed to handle data from a single XPS instrument with a single X-ray energy; in this work, the algorithm is extended to provide a simultaneous analysis tool which can handle data from multiple instruments with multiple X-ray energies. The analysis provides depth profiles for multilayer stacks that cannot be obtained by conventional data analysis methods. In this paper, metal multi-layer stack samples with total thickness greater than 10 nm are analyzed with the maximum smoothness method to non-destructively obtain depth profiles, with precise information on the chemical states of atoms in the surface layer (<2 nm) and the overall layer stack structure, which can only be obtained by analyzing the data from multiple instruments.