Identification of fragments produced from dimethylamine in a Freeman-type ion source and deposition of carbon nitride films by injecting CNH+ ions

• We proposed a methodology for carbon nitride film formation. • We employed dimethylamine as a source material. • Dominant fragments generated from dimethylamine were H + , C + , N + , CNH + , CNH 2 + and C 2 NH 6 + . • We obtained CNH + ion beams by mass-selection of dimethylamine fragment ions. • After irradiation by CNH + , carbon-rich carbon nitride films were formed on substrates. This work assessed the ion fragments generated from dimethylamine supplied to a Freeman-type ion source. H + , C + , N + , CNH + , CNH 2 + and C 2 NH 6 + were all identified. Among these, CNH + ions were selected using a mass filter and used to irradiate a substrate at energies of 18, 28, 48, 68 or 108 eV. Attempts were made to fabricate films using energy values of 18, 28 or 48 eV, and the latter two values provided viable specimens. Film thicknesses of 35 and 50 nm were obtained using ion energies of 28 and 48 eV, respectively, at a current of 0.9 A/cm 2 over a duration of 9 h. Analyses using X-ray photoelectron spectroscopy indicated that these films comprised carbon-rich carbon nitride. The 18 eV trial provided a film having a higher nitrogen-to-carbon atomic ratio, suggesting that this ratio was increased at lower ion energies.