## 3 Results and Discussion  
The optical emission spectra recorded from the glow discharge of the TMS-O\({}_{2}\)-NH\({}_{3}\) gas mixture at an ammonia gas flow ratio of 0 (i.e., TMS-O\({}_{2}\) gas mixture) and 0.5 are shown in Figure 1a,b, respectively. As shown in Figure 1a, the TMS monomer reacted with the oxygen gas, resulting in several additional emission lines other than the transition lines determined from the pure oxygen plasma shown in the inset figure. The emission lines at about 558, 777, and 844 nm were relevant to the transition lines of the oxygen atoms (O) or ions (O\({}_{2}\)+) [15; 16]. The emission lines at about 450, 482, and 518 nm were related to the carbon-containing species of CO [16; 17], whereas the emission peak at about 655 nm was assigned as the atomic emission of excited H\({}_{\alpha}\)[18; 19]. In addition, the emission lines around the short wavelengths with two strong peaks at approximately 288 nm and 312 nm emerged from the species of the SiO and OH radicals, respectively [18; 20; 21; 22]. In contrast, when ammonia gas was introduced into the gas mixture, the dominating emission lines over the OES spectrum (Figure 1b) were quite different from those of the glow discharge of the TMS-O\({}_{2}\) gas mixture. As referred to in the inset OES spectrum of Figure 1b, measured from the pure ammonia plasma, the peaks at about 314, 335, 356, and 390 nm were attributed to the transition lines of the nitrogen molecules (N\({}_{2}\)) and the ions of the nitrogen molecules (N\({}_{2}\)+) [23; 24]. The emission peaks at 426, 485, and 655 nm, in turn, corresponded to the molecular and atomic emissions of excited H\({}_{2}\), H\({}_{\beta}\), H\({}_{\alpha}\)[20; 25]. Furthermore, a significant peak at about 387 nm emerged from the CN\({}^{\prime}\)/CH transition [24; 26]. Based on the above-mentioned analyses, the oxygen-related plasma lines as well as the emission lines that emerged from the dissociation and oxidation between the oxygen and TMS monomer, such as SiO, CO, and OH species, were the main fingerprints determined from the OES spectrum recorded from the TMS-O\({}_{2}\) glow discharge. In contrast, the hydrogen- and nitrogen-related emission lines that came from the dissociation of ammonia became the fingerprint of the OES spectrum observed from the glow discharge of the TMS-O\({}_{2}\)-NH\({}_{3}\) gas mixture. It was also worth noting that the incorporation of the ammonia gas into the TMS-O\({}_{2}\) gas mixture would limit the oxidation of the TMS monomer due to the inlet oxygen gas flow rate decreasing correspondingly, and the relative intensity of the oxidation-related emission lines thus decreased sharply. Figure 2 shows the deposition rate of the film as a function of the ammonia gas flow ratio in the glow discharge. As shown in Figure 2, the deposition of the SiO\({}_{x}\) film under the glow discharge of the TMS-O\({}_{2}\) gas mixture corresponded to a high deposition rate of approximately 24.8 nm/min, while a sharp decrease in the deposition rate (\(\sim\)14.9 nm/min) was measured from the film synthesized from the ammonia gas incorporated into the reactive gas mixture at a gas flow ratio of 0.25. It implied that the deposition of the SiO\({}_{x}\) film was deeply relevant to the reduction in the oxidation-related radicals due to the decrease in the inlet oxygen gas flow rate rather than the increase in the nitrogen-related radicals. The deposition rate of the films under the TMS-O\({}_{2}\)-NH\({}_{3}\) glow discharge was gradually decreased as the gas flow ratio of the oxygen gas in the reactive gas mixture decreased and the lowest deposition rate of about 8.9 nm/min was obtained from the film synthesized from the TMS-NH\({}_{3}\) gas mixture. The FTIR spectra of the films as a function of the ammonia gas flow ratio in the glow discharge are given in Figure 3a.