Recent Status of Thin Film Analyses by XPS

Abstract

  The application of XPS for film thickness analyses of overlayer thin films, the structure analysis of multilayered thin films, the background shape analyses of thin films of varying depth distributions and the compositional depth profiling by ARXPS utilizing the maximum entropy method are described. The destructive depth profiling of organic thin films (such as ～100 nm in thickness) by cluster ion beams is also described. The film thickness analysis is applied for samples such as the oxide thickness distribution on 200 mm silicon wafers. The structure analysis has a great opportunity for applications on chemically modified surfaces. The background shape analysis is useful for both homogeneous and structured thin films. The MEM applied to ARXPS data is also useful for structured analysis for such as SiON thin films. However both background shape analysis and MEM need optimizations of the parameters using prior information about the films. On the other hand, depth profiling of organic thin films in 100 nm order thickness is successfully applied with 10 keV C₆₀ ion beam sputtering and with 0.2 keV Ar ion beam and 10 keV C₆₀ ion beam co-sputtering.