Analysis of nitrogen-doped ion-beam-deposited hydrogenated diamond-like carbon films using ERDA/RBS, TOF-ERDA and Raman spectroscopy

In this work we deposited a series of hydrogenated amorphous carbon (a-C:H) films and nitrogen-doped a-C:H films on silicon substrates using an ion-beam-deposition technique called anode layer source. We used different discharge voltages, which influence the sp2/sp3 carbon hybridization ratio, and we also varied the N2-to-C2H2 flow ratios. mposition was analysed by elastic recoil detection analysis (ERDA), to determine the hydrogen content, in combination with Rutherford backscattering spectroscopy (RBS), for the heavier elements. An additional set of experiments was conducted by time-of-flight (TOF) ERDA, which gives information not only about the hydrogen content but also about the content of other lighter elements (C, N and O) in the sample. The influence of the deposition parameters on the chemical composition and the structure of the films (studied by Raman spectroscopy) was thus evaluated. The discharge voltage did not have a measurable effect on the composition (but a decisive one on the structure), while the nitrogen flow variations were clearly proven in respective trends in the chemical composition and structure variations.