## 4 Conclusions  
For experimental realization, we synthesized amorphous BC\({}_{\rm x}\)N\({}_{\rm y}\) films by decomposition of the mixture of trimethylamine borane and nitrogen (P\({}_{\rm TMAB}\):P\({}_{\rm N2}\) = 1:1) using both LPCVD and PECVD processes at 673-973 K and 373-523 K, respectively. Various processing temperatures were used to study the effect of temperature on BC\({}_{\rm x}\)N\({}_{\rm y}\) films' properties. It should be emphasized that the type of activation of the gas phase (thermal or plasma) has a significant effect on the composition of the synthesized films. The composition of films deposited by the LPCVD method close to BC\({}_{\rm x}\) with very low nitrogen concentration. In contrast to the LPCVD films where B-C bonds were dominant, the PECVD films have BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{\rm z}\):H composition and a complex chemical structure. The broad bands of the XPS  
Figure 15: AFM images of scratch traces for PECVD BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{\rm z}\) films deposited at varied temperature: (a) 373, (b) 423, (c) 473, and (d) 523, K. Indenter orientations: 1—edge-forward and 2—face-forward.  
spectra suggest that the films are composed of different B-N and B-C-N bonds in forming the sp\({}^{2}\) B-C-N atomic hybrid configuration. Thus, the deposition technique offers the ability to control the films' properties.  
The films deposited by LPCVD exhibit the highest hardness, about 28 GPa, and the highest elastic modulus, about 243 GPa. This fact could be explained by the high amount of B-C bonds. The increase in the nitrogen content in the films, which was achieved using the PECVD method, dropped sharply the values of mechanical properties.  
The highly transparent films with a transmittance of up to 95% were obtained only in the PECVD process. The values of the refractive index and optical band gap are also sensitive to the preparation method of the films. The LPCVD films had higher refractive indexes and lower optical bandgaps.  
According to our experimental results of the decomposition of the TMAB + N\({}_{2}\) mixture, we can recommend the use of the LPCVD method to obtain the hard hydrophilic BC\({}_{\rm x}\)N\({}_{\rm y}\) films and the PECVD method for the deposition of the transparent hydrophilic BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{\rm z}\):H films.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app13084959/s1](https://www.mdpi.com/article/10.3390/app13084959/s1)]([https://www.mdpi.com/article/10.3390/app13084959/s1](https://www.mdpi.com/article/10.3390/app13084959/s1)), Figure S1: Dependence of (a) hardness and (b) [PERSON]'s modulus on the indentation depth for the LPCVD BC\({}_{\rm x}\)N\({}_{\rm y}\) film (T\({}_{\rm dep}\) = 773 K); Figure S2: XRD patterns of Si(100) substrate and BC\({}_{\rm x}\)N\({}_{\rm y}\) films deposited by LPCVD and PECVD processes at 973 and 523 K, respectively.  
Conceptualization, S.V.B. and M.L.K.; methodology, S.V.B. and M.L.K.; validation, S.V.B.; formal analysis, E.A.M., V.R.S., A.A.S. ([PERSON]), A.N.K., A.A.S. ([PERSON]), I.P.A., M.N.K., I.V.Y. and A.G.P.; investigation, E.A.M., V.R.S., A.N.K., A.A.S. ([PERSON]), I.P.A. and I.V.Y.; writing--original draft preparation, S.V.B.; writing--review and editing, V.S.S. and M.L.K.; visualization, S.V.B., E.A.M., A.N.K., A.A.S. ([PERSON]), I.P.A., M.N.K. and I.V.Y.; supervision, M.L.K.; project administration, M.L.K.; funding acquisition, M.L.K. All authors contributed to the discussion and interpretation of the results. All authors have read and agreed to the published version of the manuscript.  
The research was supported by the Ministry of Science and Higher Education of the Russian Federation, project N 121031700314-5.  
Not applicable.  
The authors thank [PERSON] for the Raman spectroscopy study, [PERSON] for the XRD study, and [PERSON] for visualization of a part of data.  
The authors declare no conflict of interest.