Raman spectroscopy analysis of the chemical structure of diamond-like carbon films deposited via high-frequency inclusion high-power impulse magnetron sputtering

• Published in: Diamond and related materials 2024-02, Vol.142, p.110768, Article 110768
• Main Authors: Fukue, Hiroyuki, Nakatani, Tatsuyuki, Takabayashi, Susumu, Okano, Tadayuki, Kuroiwa, Masahide, Kunitsugu, Shinsuke, Oota, Hiroki, Yonezawa, Ken
• Format: Article
• Language: English
• Subjects: Diamond-like carbon; High-power impulse magnetron sputtering; Multipeak fitting; Raman spectroscopy; sp2 C=C cluster model
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2023.110768

Aiming to develop a new high-power impulse magnetron sputtering (HiPIMS) method to further improve the functionality of thin films, we previously designed a high-frequency inclusion HiPIMS (HF-HiPIMS) power supply for obtaining high-performance diamond-like carbon (DLC) films. Herein, the chemical structure of DLC films deposited via HF-HiPIMS was analyzed using Raman spectroscopy. First, the peak positions were fixed, and the number of fitting parameters was reduced by conducting a waveform separation of the initial Raman spectrum using a differential spectrum method. Next, the Raman spectra of the DLC films subjected to five-peak separation and two-peak separation analyses were compared, and the limitations of the two-peak separation analysis are discussed. Furthermore, the relation between the Raman parameters of the five-peak separation analysis and film properties suggested that Raman spectroscopy could be used to estimate the sp3 C–C/(sp3 C–C + sp2 C=C) ratio. [Display omitted] •DLC films deposited via HF-HiPIMS were analyzed using Raman spectroscopy.•Five-peak Raman spectra were separated by differential spectra.•Number of parameters related to peak positions was reduced.•sp3 C–C ratio was evaluated using Raman parameters.