## 3 Results and Discussion
### Films' Composition and Chemical Bonding State
#### 3.3.1 EDX Spectroscopy Data  
The EDX spectra confirmed the presence of boron, carbon, nitrogen, and oxygen. Experimental chemical maps based on EDX data show uniform elemental distribution over the sample's site. Figure 4 shows the data for two films obtained by LPCVD (T\({}_{\rm dep}\) = 973 K) and PECVD (T\({}_{\rm dep}\) = 373 K) and having B\({}_{0.67}\)C\({}_{0.24}\)N\({}_{0.08}\)O\({}_{0.01}\) and B\({}_{0.22}\)C\({}_{0.36}\)N\({}_{0.19}\)O\({}_{0.24}\) compositions, respectively. Figure 5 presents the change in the elemental composition of both LPCVD and PECVD films with increasing T\({}_{\rm dep}\). The composition of LPCVD films smoothly changes from B\({}_{0.80}\)C\({}_{0.14}\)N\({}_{0.04}\)O\({}_{0.02}\) to B\({}_{0.67}\)C\({}_{0.24}\)N\({}_{0.08}\)O\({}_{0.01}\) for the temperature interval from 673 K to 973 K, at this [N]:[B] equal to 0.05-0.01 in these films is two orders of magnitude lower than in the used precursor. Meanwhile, the using a mixture of TMAB with ammonia (P\({}_{\rm TMAB}\):P\({}_{\rm NH3}\) = 1:1) at T\({}_{\rm dep}\) = 973K led to the formation of a film with [N]:[B] close to 1 [36,54] (Table 1), which indicates the inertness of nitrogen compared to ammonia in the process. Figure 4: SEM-EDX elemental mapping of BC\({}_{\rm x}\)N\({}_{\rm y}\) films synthesized by (**a**) LPCVD and (**b**) PECVD methods from TMAB+N\({}_{\rm z}\) mixture at 973 K and 373 K, respectively. It should be noted that all LPCVD films exhibited a small concentration of oxygen which varied within 1-2 at.%. As the temperature rises, the boron content decreases and the carbon and nitrogen contents increase. A similar trend was found in the synthesis of LPCVD BC\({}_{\rm x}\)N\({}_{\rm y}\) films from a mixture of triethylamine borane and ammonia. The authors of [60] explained the increase in carbon content at high temperatures by the decomposition of triethylamine molecules into nitrogen and hydrocarbons with a further decomposition of the latter. According to [55], as the substrate temperature increased, the boron concentration also decreased while the nitrogen and carbon concentrations increased for LPCVD BC\({}_{\rm x}\)N\({}_{\rm y}\) films deposited from a mixture of dimethylamine borane and argon. A high percentage of the boron content suggests that the composition of these films is close to boron carbide, the stoichiometry of which can vary within the interval of B\({}_{4}\)C-B\({}_{10.1}\)C [8; 9; 10]. In our case, the [B]:[C] ratio changes from 5.7 to 2.8. It can be assumed that high-temperature films also contain carbon as an elementary phase, which will be confirmed later by Raman spectroscopy. Plasma-stimulated processes can significantly reduce the film deposition temperature. The T\({}_{\rm dep}\) in this case lies in the interval from 373 K to 873 K. The contents of boron and nitrogen in the films synthesized up to T\({}_{\rm dep}\) = 573 K increase almost linearly from 22 to 39 at.% and from 19 to 40 at.%, respectively (Figure 5b). While the contents of carbon and oxygen decrease from 36 to 12 at. % and from 24 to 13 at.%, respectively. For the high-temperature films (T\({}_{\rm dep}>\) 573 K), the boron content practically does not change, [C] increases to 25 at.%, while [N] and [O] slightly decrease. Based on the previously obtained data on decomposition of organoboron compounds in the PECVD processes, it can be assumed that the increase in the carbon content can be associated with the deposition of graphite-like carbon [38; 61]. The ratio of boron to nitrogen in PECVD films is approximately equal to 1, which corresponds to their ratio in the precursor. The high oxygen content in these films should be noted. In this regard, it is more correct to describe the films obtained in PECVD process as BC\({}_{\rm x}\)N\({}_{\rm y}\)O\({}_{\rm z}\).