Soft X-ray spectroscopy and the non-destructive chemical state analysis of thick films and surface layers (10-1000 nm)

The use of low-energy electron beams to initiate X-ray spectroscopic analysis of surface layers, 10-1000 nm thick, is described. The probed depth is controlled by the energy of the bombarding electrons in the range 3-12 kV and the characteristic soft X-rays emitted by the sample are analyzed by a wavelength dispersive spectrometer (Telsec Betaprobe). Soft X-rays can exhibit large "chemical shifts". This property is used to determine the chemical state of elements such as Al in alumina layers on Al metal, Fe and Cr in oxide layers on steel, and boron in silica layers containing traces of B and phosphorus. Spectra. 3 ref.--AA(UK).