SIMS Analysis of Carbon-Containing Materials: Content of Carbon Atoms in sp2 and sp3 Hybridization States

We have studied a new approach to the analysis of carbon-containing materials by secondary ion mass spectrometry (SIMS), which allows determining the contents of carbon atoms in sp2 and sp3 hybridization states. According to this, the main SIMS parameter characterizing the atomic concentration N(sp3) is defined as the intensity ratio of C8/C7 secondary cluster ion peaks. Based on the results of SIMS analysis of several test compositions, a calibration dependence of N(sp3) versus C8/C7 peak intensity ratio has been obtained. The depth profiles of N(sp3) for diamond-like carbon (DLC) grown on diamond and silicon substrates were obtained, which showed (i) N(sp3) variation from 0.3 to 0.6 depending on the DLC growth regime and (ii) inhomogeneous distribution of N(sp3) in depth of the samples.