A comparative study of two ion beam techniques used in the analysis of porous silicon

A comparative study was made between a combination of alpha-RBS and NRA and proton backscattering (BS) for the analysis of as-prepared and metallised porous silicon samples of different thicknesses and porosities. In general, alpha-RBS and NRA was found to give better information on the composition of surface metal layers and the content within porous silicon of oxygen and carbon, especially when the amounts of oxygen and carbon are small (simila r to 2-4 at.%) and when their amounts are high enough to cause peak overlap in BS spectra. However, BS was shown to have advantages for the analysis o f metal penetration at depths of more than 1 mu m or when the samples were covered with a layer of metal several tenths of a micron in thickness. (C) 1999 Elsevier Science B.V. All rights reserved.