The feasibility of an XPS expert system demonstrated by a rule set for carbon contamination

A 'surface analysis', no matter how well authenticated, is rarely satisfyin g as a single piece of information. Many users require the quantified distr ibution of observed species as a function of depth. In this paper it is arg ued that adding knowledge-based inferencing to the data-system is required if the full interpretation of spectra is to be made possible. The basic pri nciples of an expert system are introduced and a preliminary set of rules f or the recognition of carbon as a contamination overlayer are proposed. Bot h the logical steps taken by the expert system in progressing towards ident ification of the C peak as overlayer contamination and the scientific knowl edge on which each rule is based are explained. Once identified as contamin ation, use of this information in proceeding further with the expert system analysis is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.