Electric Characteristics of Si₃N₄ Films Formed by Directly Radical Nitridation on Si(110) and Si(100) Surfaces

Abstract

High quality Si 3 N 4 film was formed by the nitridation of Si(110) surface using radical NH. It was found that the gate leakage current through the Si 3 N 4 film is three orders of magnitude smaller than that through the conventional SiO 2 film, and the interface states density at midgap for Si 3 N 4 /Si interface is less than 5 Â 10 10 eV À1 cm À2 . High-resolution soft-X-ray-excited Si 2p spectra were measured for the Si 3 N 4 films formed on Si(100), Si(110) and Si(111). It was found that the crystal orientation of the Si substrate affects the amount of intermediate nitridation states of Si at the Si 3 N 4 /Si interface.

Nitridation of Si by N[sub 2] Electron Cyclotron Resonance Plasma and Integration with ScO[sub x] Deposition

“…In the following, the nitrided layer is addressed as SiN x , even though O is present in this layer. An ͓O͔/͓N͔ ratio of about 40% was reported by Higuchi et al 15 after nitridation in NH 3 microwave plasma with increasing O concentration near the surface of the nitrided layer. A higher ͓O͔/͓N͔ ratio of about 54% was reported by Kobayashi et al for nitridation using N 2 plasma obtained by the low energy electron impact method.…”

“…The presence of intermediate nitridation states of Si, i.e., Si atoms bonded to less than four N atoms, were reported for nitridation in NH 3 plasma. 15 Figure 3 shows a cross-sectional TEM image of a sample of series B subjected to nitridation for 120 s. The silicon nitride layer is clearly observed for these nitridation times. The presence of N in this layer was confirmed by energy-dispersive X-ray measurements, although a quantitative evaluation of the composition was not possible.…”

“…In fact, oxidation of the SiN x surface due to exposure to air was reported for nitrided layers using NH 3 plasma, in which not fully nitrided Si states were detected. 15 Either way, it is concluded that the formation of a silicon oxide layer at the Si interface is prevented.…”

“…The nitridation of silicon can be achieved by thermal processing in NO or NH 3 atmospheres 7-12 or by different plasma techniques, such as NH 3 /N 2 and N 2 O/N 2 plasmas, 13 N 2 remote plasma, 12,14 a Xe/NH 3 microwave plasma, 15 or N 2 plasma obtained by the low energy electron impact method. 16 In these works, a decrease in the leakage current is observed with respect to un-nitrided substrates.…”

Formation of Aligned α-Si3N4 Microfibers by Plasma Nitridation of Si (110) Substrate Coated with SiO2

“…Si 3 N 4 has many different crystal structures, among which α-Si 3 N 4 , β-Si 3 N 4 , and γ-Si 3 N 4 are common phases. Both α-Si 3 N 4 and β-Si 3 N 4 can be formed under ambient conditions at high temperatures, while γ-Si 3 N 4 exists under high temperature and high pressure [3][4][5]. In addition, crystalline Si 3 N 4 synthesis, generally in polycrystalline microstructure, has been widely conducted by nitridation of Si and SiO 2 powders at high temperature.…”