Electron spectroscopy with CrK beta photons: high energy XPS and X-AES

High energy XPS was used to measure electron attenuation lengths over a kin etic energy range of similar to 2500 to similar to 5900 eV. For these measu rements the substrate overlayer method has been employed in conjunction wit h Cr K-beta (hv=5946.7 eV) and synchrotron radiation (hv=1800-4600 eV) exci ted XPS. Polyparaxylylene films were deposited 'in situ' on a gold substrat e and the attenuation of the photoelectron signals from the Au 3s, 3d, 4p, 4d and 4f levels was monitored. The results were confirmed with similar mea surements of the attenuation of the Au 4f substrate peaks excited by synchr otron radiation. It was found that the typical attenuation length at 5900 e V is 7.5 nm and over the measured energy range it follows an E-0.5 dependen ce in line with previous expectations. A set of 14 atomic sensitivity facto rs of a range of elements important for polymers and substrate standards as well as Auger parameters of several metals and alloys were measured using Cr K-beta radiation. The values of the sensitivity factors obtained showed broad similarities to those employed for low energy sources. Auger paramete r studies of metals and alloys require excitation of photoelectrons and Aug er electrons from the core atomic levels of the elements of interest, as we ll as an increased analysis depth since the results are often interpreted i n relation to the bulk rather the surface properties of the material. This paper shows that these requirements are met when Cr K-beta is used as an ex citation source. The characterisation of the Cr K-beta source in terms of a chievable resolution and sensitivity is also briefly discussed. (C) 2001 El sevier Science B.V. All rights reserved.