Investigation of the morphology of porous silicon by Rutherford Backscattering Spectrometry

The pore walls of a porous Si sample of columnar type were coated by SnO2 using the sol-gel technique. The sample was characterised by Rutherford Backscattering Spectrometry (RBS). The Sn signal in the RBS spectra revealed that the coating was homogeneous in depth. The low energy edge and the total width of the Sn peak showed significant variations with sample tilt angle yielding information on the 3D morphology of the porous layer. These effects could be simulated by Monte Carlo type calculations of RBS measurements on 3D structures.