Comparison of elastic resonance and elastic recoil detection in the quantification of carbon in SiGeC

The carbon concentrations of chemical vapor deposition grown Si_1-x-yGe_xC_y (0.25 < x < 0.37 and 0.01 < y0.12) layers on (100) Si with uniform composition profiles were quantified by two ion analysis techniques. Measurements made with backscattering spectrometry using a 4.295 MeV He²⁺ incident ion were compared to compositions predicted by elastic recoil detection (ERD) using a 24 MeV Si⁵⁺ incident ion. To enhance the carbon scattering cross section for the backscattering measurements, the 4.265 MeV ¹²C(α, α)¹²C elastic resonance reaction was used. The carbon concentrations of the films were calculated by integrating the resonant scattering cross section using the energy width of the layer as the limits of integration. The results of this backscattering analysis technique were compared to the predicted carbon concentrations obtained by ERD. It was found that the predictions of these techniques correlated within the uncertainty of each method.