Quantitative Chemical State Analysis of Tin Oxides (Sn, SnO, and SnO2) with High-Energy Resolution AES

Abstract

The chemical state analysis of AES is, at present, performed only for some limited elements. This is because the peak broadness and the shape complexity of Auger spectra make it very difficult to identify the superimposed spectrum as each individual specific chemical state. In this report an advanced chemical state analysis of AES is proposed. This analysis is based on a file of standard spectra of elements with well-defined chemical states, the spectra of which are acquired with high energy resolution of AES. As an example, this method was applied to the depth profile of an tin oxide layer formed on a pure tin plate. The spectra of Sn MNN and O KLL were measured with an energy resolution of 0.1%. Every observed spectra of Sn MNN was separated to three oxidation sates : Sn 4＋ , Sn 2＋ and Sn 0 , using the filed standard spectra of SnO2, SnO and Sn. Likewise, O KLL spectra was separated to two bonding state : O 2− bonding to Sn 2＋ and O 2− bonding to Sn 4＋. Moreover, we proposed new quantity method to estimate an atomic concentration depending on the chemical bonding state by comparison with the absolute intensity of the standard spectrum.