Rutherford backscattering spectrometry analysis of InGaAs nanostructures

In this work, the authors demonstrate that Rutherford backscattering spectrometry (RBS) can be extended from a metrology concept applied to blanket films toward a method to analyze confined nanostructures. By a combination of measurements on an ensemble of devices and extensive simulations, it is feasible to quantify the composition of InGaAs nanostructures (16–50 nm) embedded periodically in an SiO₂ matrix. The methodology is based on measuring multiple fins simultaneously while using the geometrical shape of the structures, obtained from a transmission electron microscopy analysis, as input for a multitude of trajectory calculations. In this way, the authors are able to reproduce the RBS spectra and to demonstrate the sensitivity of the RBS spectra to the quantitative elemental composition of the nanostructures and to variations of their shape and mean areal coverage down to one nanometer. Thus, the authors establish RBS as a viable quantitative characterization technique to probe the composition and structure of periodic arrays of nanostructures.