The films, prepared by LPCVD and PECVD from the TMAB + He mixture at 723 K, had the compositions of B\({}_{0.72}\)C\({}_{0.23}\)N\({}_{0.04}\)O\({}_{0.01}\) and B\({}_{0.33}\)C\({}_{0.46}\)N\({}_{0.21}\)O\({}_{0.01}\), respectively [37]. The authors also reported on the effect of the type of additional gases, such as H\({}_{2}\), He, N\({}_{2}\), and NH\({}_{3}\), the partial pressure of ammonia, and the substrate temperature on the composition of the deposited films. In the work [36], the BC\({}_{\rm x}\)N\({}_{\rm y}\) films deposited by LPCVD method at 973 K were characterized by XPS and TXRF-NEXAFS. The composition of the films produced from TMAB and its mixtures with He and N\({}_{2}\) is close to a B-C bond containing compound with an atomic relation of [B]:[C] = 1:1. The addition of ammonia led to an increase in the nitrogen content in the films and the formation of a compound with an atomic ratio of [B]:[C]:[N] = 1:1:1. For BC\({}_{\rm x}\)N\({}_{\rm y}\) films deposited by the PECVD method at 673 K [37], the introduction of ammonia reduces the carbon content, increases the nitrogen content, and leads to the formation of B-N bonds. All authors note the presence of oxygen in the films. Its content is highly dependent on the method of film formation. In LPCVD films, the oxygen content is equal to 1-4 at.%. Films deposited in plasma-stimulated processes have an oxygen content up to 15 at.% and up to 51 at.% in the case of RF PECVD and MW PECVD, respectively (Table 1). Despite the above-mentioned studies with respect to the use of mixtures of TMAB with He, H\({}_{2}\), and NH\({}_{3}\), there is a lack of systematic data concerning the influence of nitrogen addition on the properties of BC\({}_{\rm x}\)N\({}_{\rm y}\) films. There are several works on the use of the TMAB + N\({}_{2}\) mixture in the MW PECVD process [41]. Ammonia is most often used to introduce nitrogen into films. It is known that nitrogen is less reactive from these two nitrogen-containing gases, due to the stronger N\(\equiv\)N than N-H binding [42]. However, the advantage of nitrogen is the absence of hydrogen in its molecule [43]. As can be seen from Table 1, the authors paid attention to the study of the mechanical properties (hardness and Young's modulus) and the optical ones (refractive index and transmittance) of BC\({}_{\rm x}\)N\({}_{\rm y}\) films. The maximum hardness value of 34 GPa was obtained for LPCVD films using TMAB + He mixture. The refractive index can be varied over a wide range from 1.6 to 2.8 by varying the films' composition. Highly transparent films can be obtained in the RF PECVD processes using TMAB + NH\({}_{3}\) mixture. It should be emphasized that information on the values of the optical band gap, wettability, and surface free energy is absent for films deposited using TMAB. The present paper focuses on the investigation of a synthesis of BC\({}_{\rm x}\)N\({}_{\rm y}\) films by LPCVD and RF PECVD methods using the TMAB+N\({}_{2}\) initial mixture and on the study of the types of chemical bonds in films and physical properties depending on the chemical structure. In the present work, the synthesis temperature was chosen as a variable parameter.