Probing the spatial dimensions of nanoscale patterns with Rutherford backscattering spectrometry

Abstract

We realize the quantitative determination of the spatial dimensions of nanopatterns using Rutherford back-scattering spectrometry (RBS) with a mm-sized ion beam. The methodology is based on the effects of the nanopatterns on the RBS signal from the substrate. We demonstrate the approach with the study of a periodic pattern of 35 nm wide and 75 nm high SiO2 lines which have a periodicity of 90 nm. We analyse the relation between the features in the experimental spectra and the properties of the nanostructures. Current voxel-based simulation software allows to reproduce many of the experimental observations well. However, we found that the present simulation software inadequately incorporates the effect of the angular spread due to the finite detector size. We propose a method to model the effect more accurately and through this we demonstrate a dramatically improved agreement with the experimental spectra.