## 3 Results and Discussion
### Functional Characteristics of BC\({}_{x}\)N\({}_{y}\) Films
#### 3.4.3 Mechanical Properties
For comparison, consider the literature data obtained by scratch-test with the Berkovich indenter. The magnetron sputtered BC\({}_{x}\)N\({}_{y}\) films had values of L\({}_{c2}\) equal to 18-30 mN depending on the films' composition [102]. In another study, the values of L\({}_{c1}\) = 32 mN and L\({}_{c2}\) = 25 mN were obtained for the magnetron sputtered BC\({}_{x}\)-like film; and critical loads for BC\({}_{x}\)N\({}_{y}\) films led in the intervals of L\({}_{c1}\) = 12-57 mN and L\({}_{c2}\) = 8-41 mN [96]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \(\mathbf{T_{dep}}\)**K** & **Film Composition** & **H, GPa** & **E, GPa** & **R, \%** \\ \hline
773 & B\({}_{0.80}\)C\({}_{0.15}\)N\({}_{0.05}\)O\({}_{0.00}\) & 27.3 \(\pm\) 3.5 & 243 \(\pm\) 25 & 71 \\
823 & B\({}_{0.77}\)C\({}_{0.17}\)N\({}_{0.05}\)O\({}_{0.01}\) & 27.6 \(\pm\) 3.1 & 230 \(\pm\) 16 & 70 \\
873 & B\({}_{0.75}\)C\({}_{0.19}\)N\({}_{0.06}\)O\({}_{0.01}\) & 27.4 \(\pm\) 4.4 & 247 \(\pm\) 28 & 71 \\
923 & B\({}_{0.70}\)C\({}_{0.21}\)N\({}_{0.07}\)O\({}_{0.02}\) & 28.2 \(\pm\) 3.8 & 236 \(\pm\) 21 & 70 \\
973 & B\({}_{0.67}\)C\({}_{0.25}\)N\({}_{0.08}\)O\({}_{0.00}\) & 24.3 \(\pm\) 4.1 & 221 \(\pm\) 26 & 74 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Mechanical properties of LPCVD BC\({}_{x}\)N\({}_{y}\) films. Figure 12: Temperature dependencies of (**a**) hardness, Young’s modulus, and (**b**) the elasticity index H/E and plasticity index H\({}^{3}\)/E\({}^{2}\) of LPCVD BC\({}_{x}\)N\({}_{y}\) films. The values of H and E of PECVD films deposited at T\({}_{\rm dep}\) = 373-523 K are significantly smaller than for LPCVD films and equal to 0.76-1.40 GPa and 25-26 GPa, respectively (Figure 14 and Table 8). It should be emphasized that these hardness values are higher than that of polycrystalline h-BN powder (H = 0.05-0.6 GPa) [103]. A significant decrease in the values of H and E compared to LPCVD films is associated with the dominance of \"softer\" sp\({}^{2}\) B-N and sp\({}^{2}\) B-C-N bonds and a smaller number of B-C bonds [3,104,105]. The presence of hydrogen- and oxygen-containing bonds also contributed to the decrease in values of mechanical performances [52]. The elasticity and plasticity indexes (Figure 14b) and recovery (Table 8) are also significantly lower than those of LPCVD films. Figure 14: Temperature dependencies of (**a**) hardness, Young’s modulus, and (**b**) the elasticity index (H/E) and plasticity index (H\({}^{3}\)/E\({}^{2}\)) of PECVD BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{2}\) films. Figure 13: AFM images of scratch traces for LPCVD BC\({}_{\rm x}\)N\({}_{\rm y}\) films deposited at varied temperatures: (**a**) 773, (**b**) 823, (**c**) 873, (**d**) 923, and (**e**) 973 K. Indenter orientations: 1—edge-forward and 2—face-forward. (**f**) Temperature dependence of critical loads of LPCVD BC\({}_{\rm x}\)N\({}_{\rm y}\) films. The adhesion of the PECVD BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{\rm z}\) films to the Si(100) substrate was evaluated by a scratch test under the same conditions as for LPCVD films (Figure 15). It should be noted that due to the low mechanical properties of these films, the indenter reaches the substrate almost at the beginning of the scratch under loads L\({}_{\rm c1}\) and L\({}_{\rm c2}\). Wherein scratching PECVD films, at both angles of penetration of the indenter (edge- and face-forward), no delamination of the film material is observed, but only its extrusion occurs. Such a reaction to the penetration of an indenter is characteristic of soft films, which are the studied PECVD samples. Based on the scratch behavior of the PECVD coating, it can be assumed that the interfacial shear stress with the silicon substrate is less than the shear strength of the film itself as a softer component.