Quantification of boron in a SiGe epilayer using ion beam analysis

• A hybrid RBS–NRA referencing approach is developed to quantify the absolute boron content in thin films. • A self-supporting B/Si 3 N 4 film is fabricated, quantified by RBS, and then used as a reference in NRA measurements. • The approach enables full elemental analysis of an in-situ boron-doped SiGe epitaxial layer. • Detailed uncertainty analysis demonstrates the high accuracy and traceable uncertainty of this approach. In semiconductor technology, boron-doped silicon–germanium compounds have attracted significant attention due to their application in strain engineering to enhance the carrier mobility. One of the current challenges in this context is the accurate quantification of the concentration of boron, since many analytical techniques require a reference standard with a known and traceable concentration. In this study, we present a method to quantify the absolute amount of boron in thin films by combining substrate-less Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). First, a substrate-less boron pellicle is realized for which the absolute amount of boron is quantified with RBS. Then, the obtained absolute standard is used as a reference for the analysis with the 11 B(p,α 1 )2α nuclear reaction at a proton energy of 640 keV. The strength of the RBS-NRA hybrid approach is illustrated with the analysis of a boron doped SiGe epilayer, demonstrating the traceable uncertainty and an accuracy of 1.5 %. More generally, the method can be employed to certify standards of 11 B in various compounds that are needed for other analytical techniques, such as secondary ion mass spectrometry (SIMS).