Effect of Amorphous Silicon Carbide Interlayer on Diamond-Like Carbon Film Structure and Film Hardness

<jats:p>This study was performed to improve the adhesiveness of a diamond-like carbon (DLC, a-C:H) layer film with an a-SiC interlayer. In previous studies, an a-SiC/DLC layer film was formed and changes in the DLC film structure and hardness caused by the thickness of the a-SiC layer were examined. After the a-SiC interlayer thickness increased and the G-peak position shifted to a lower frequency, the peak began shifting to higher frequencies. The G-peak position reached a minimum frequency at a film thickness of approximately 0.3 μm. In contrast, as the thickness of the a-SiC interlayer increased, the FWHM of the G-peak position increased almost monotonically and the number of sp<jats:sup>3</jats:sup> bonds also increased. As the interlayer thickness increased, the hydrogen content in the DLC film increased, and then began decreasing, with the interlayer film thickness exhibiting a local maximum at approximately 0.3 μm. As for the DLC film hardness, a correlation between the hydrogen content and half width of the G-peak position was observed. When the hydrogen content was ≤40 at%, a positive correlation with the FWHM (G) was observed, and when the hydrogen content was 40 at% or above, a negative correlation with FWHM (G) was found. The adhesiveness of the DLC film and substrate was improved by forming an a-SiC thin film as an interlayer. The effects of the a-SiC thin film on DLC film quality were determined.</jats:p>