Experimental determination of the inelastic mean free path of electrons in GaSb and InSb

The inelastic mean free path IMFP.of electrons is a fundamental material parameter for quantitative surface- and thin-film analysis by AES and XPS. Experimental determination of IMFP is based on the elastic peak electron spectroscopy EPES.The intensity of the elastic peak recorded for the sample is compared with that of the Ni reference. The IMFP is evaluated from the Monte Carlo MC.calculations of the elastic backscattering probability. The MC algorithm is based on elastic scattering cross-sections from the NIST 64 database and IMFP values of Ni. Experiments have been carried out in three laboratories working with different types of electron spectrometers and energy ranges: HSA, Es0.2–5 keV; CMA, Es0.2–2 keV, and RFA, Es0.2–1.5 keV. GaSb 100.and InSb 100.samples have been cleaned and their surface layer amorphized by an Arq ion bombardment at Eions2 keV. The surface composition after cleaning was checked in situ by XPS. No metallic Ga, In or Sb phases were evidenced by plasmon losses on the surface after Eions2 keV Arq ion treatment. The MC calculations were based on the real surface composition. Thus, the IMFP values experimentally obtained for the ion bombarded samples can be considered as the volume parameters for E)0.5 keV. A reasonable agreement was found with the calculated IMFP data of NIST and with other theoretically determined values of the IMFP. q1999 Elsevier Science B.V. All rights reserved