PIXE detection limit for aluminium thin film deposited on Si-based matrix

Abstract

The aim of this work is to show the capability of the PIXE technique as a rapid, non-destructive and accurate quantification method on silicon (Si) and in Si-based matrix. For this purpose, an aluminium (Al) thin film (2.5nm) deposition on silicon and silicon carbide substrates was carried out using effect joule evaporation. In order to improve the sensitivity for Al determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3MeV) with a different incident angles (0°, 60°, and 80°). Proton beam energy of 0.3MeV and 80° tilting angle permits a more accurate determination of Al/Si with high sensitivity within few minutes of acquisition time and with a LOD less than 1.2×1015at/cm2. However, the LOD of Al decreases by one order of magnitude when SiC substrate is used instead of Si. Hence, these optimal parameters were used to determine the concentration of Al doping in thin homoepitaxial SiC layer. It was found that the Al/Si ratio was varied from 0.066 to 0.36 when the incident angle varied from 0 to 80°.