Estimation of the thickness or composition of a covering layer on a solid by XPS or AES

A method is proposed for semi-quantitative determination of the thickness or composition of a covering layer on a solid by XPS or by micro-AES using neither a series of standard samples nor argon-ion etching. In the case of XPS, the thickness or relative composition of the covering layer is calculated by means of the intensity ratio between one element and another in a specimen and using physical parameters such as inelastic mean free paths of electrons and photoionization cross-sections. In the case of AES, the physical parameters for the quantification can be eliminated by using the ratio of the relative intensity for two elements in the sample to that in a suitable, comparable reference.