## 1 Introduction  
Dielectric films, such as silicon nitride (SiN\({}_{\mathrm{x}}\)), are extensively studied as etch stop layers, gate dielectrics, stress liners, charge trap layers, and as spacer applications in front-end-of-line (FEOL) semiconductor wafer processing. The main applications utilize SiN\({}_{\mathrm{x}}\) films as gate spacers in dynamic random access memory, logic devices, and the charge trap layer of vertical NAND flash devices [1, 2]. These spacer films act as an oxygen or dopant out-diffusion barrier and control the source/drain doping profiles. They also act as a film to prevent etching damage during later processing. The requirements of a suitable SiN\({}_{\mathrm{x}}\) spacer film include resistance to etching and high conformality [3, 4, 5, 6]. However, it has been a challenge to develop new methods to ensure these requirements. Recently, gate spacer research has considered methods to control the dielectric constant by doping carbon into SiN\({}_{\mathrm{x}}\) thin films to reduce the resistive-capacitive (RC) delay [7]. A variety of methods exist for depositing SiN\({}_{\mathrm{x}}\) thin films, including low-pressure chemical vapor deposition (LPCVD), plasma-enhanced CVD (PECVD), and atomic layer deposition (ALD). Commonly used LPCVD is capable of producing highly conformal films at high temperature (approximately at 700 \({}^{\circ}\)C), with excellent etching properties and low hydrogen content [1, 8, 9]. However, the high deposition temperature exceeds the thermal budget of the gate spacer fabrication process. SiN\({}_{\mathrm{x}}\) films using PECVD can be grown at low temperatures (\(\leq\)400 \({}^{\circ}\)C); however, these films show low quality and poor step coverage [8, 9, 10]. As device feature size is miniaturized, the allowed thermal budget during processing decreases and film quality, such as conformality, must remain high [11]. The ALD method satisfies these requirements as a gate spacer fabrication technique because it provides precise thickness control, perfect step coverage, and high quality, even at low temperatures due to its self-limited reaction [12; 13; 14; 15]. Thermal ALD induces reaction kinetics at the surface by heating the substrate or chamber, while plasma-enhanced ALD (PEALD) improves low-temperature reactivity by supplying additional energy from the plasma [10]. PEALD provides a variety of advantages for deposition of thin films compared to thermal ALD and other vapor phase deposition techniques. The high reactivity of the plasma generated during plasma-assisted ALD widens the choice of processing conditions and materials [10; 11; 12; 13]. Also, the plasma radicals and ion fluxes are very high at the deposition surface in PEALD. Short plasma exposure times allow the entire surface to be deposited uniformly. However, the ion energy reaching the surface is so high that it can damage the surface. On the contrary, remote plasma ALD (RPALD) was developed to reduce plasma-induced damage on the surface. The reaction chamber and the plasma generation region are separated. There is much higher radical flux that contributes to deposition towards the substrate than direct plasma. In the case of PEALD, the gas temperature is easily changed in accordance with the substrate temperature change, which in turn affects the density of gaseous species and the generation of plasma species. The RPALD allows flexible control of plasma composition and properties at the substrate's location, making it well-suited for process design [8; 16; 17; 18; 19]. The ALD of SiN\({}_{\mathrm{x}}\), silicon chlorides (e.g., SiCl\({}_{4}\), SiH\({}_{2}\)Cl\({}_{2}\), and Si\({}_{2}\)Cl\({}_{6}\)) have been studied as silicon precursors along with reactants such as NH\({}_{3}\), NH\({}_{3}\) plasma, or N\({}_{2}\)H\({}_{4}\). The use of chlorosilane requires a high deposition temperature and causes detrimental effects such as particle formation, byproducts, and undesired chlorine incorporation. Therefore, chlorine-free precursors such as silane or aminosilane are in high demand [1; 3; 9; 10; 13].