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.