Acoustics at nanoscale: Raman-Brillouin scattering from thin silicon-on-insulator layers

We report on Raman-Brillouin scattering from thin single silicon layers. Starting from a 33 nm silicon-on-insulator structure, a series of layers with progressively decreasing thicknesses was prepared using a chemical treatment consisting of oxide stripping/ formation cycles. In order to determine these thicknesses, experimental Raman-Brillouin spectra are compared to calculations performed in the frame of the photoelastic model. We demonstrate that subnanometer changes in the silicon layer thickness can be derived from a proper analysis of the spectral response. It is shown that a 1 nm thick oxide forms during the chemical treatment. (C) 2010 American Institute of Physics. [doi:10.1063/1.3499309]