The effect of composition on the bond structure and refractive index of silicon nitride deposited by HWCVD and PECVD

• Published in: Thin solid films Vol. 517; no. 12; pp. 3499 - 3502
• Main Authors: Verlaan, V., Verkerk, A.D., Arnoldbik, W.M., van der Werf, C.H.M., Bakker, R., Houweling, Z.S., Romijn, I.G., Borsa, D.M., Weeber, A.W., Luxembourg, S.L., Zeman, M., Dekkers, H.F.W., Schropp, R.E.I.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30.04.2009; Elsevier
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Hot Wire CVD; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Silicon nitride; Surface and interface electron states; Hot Wire CVD; Silicon nitride; Hot filament chemical vapor deposition; Electronic properties; RBS; Fourier transform spectroscopy; Refractive index; Composition effect; Thin films; Energy gap; Amorphous hydrogenated material; Optical properties; Silicon; PECVD; Quantitative chemical analysis; Stretching; Radiofrequency sputtering
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.01.065

Silicon nitride (SiN x ) is a material with many applications and can be deposited with various deposition techniques. Series of SiN x films were deposited with HWCVD, RF PECVD, MW PECVD and LF PECVD. The atomic densities are quantified using RBS and ERD. The influence of the atomic densities on the Si–N and Si–Si bond structure is studied. The density of N–N bonds is found to be negligible. New Si–N FTIR proportionality factors are determined which increase with increasing N/Si ratio from 1.2 · 10 19 cm − 1 for Si rich films (N/Si = 0.2) to 2.4 · 10 19 cm − 1 for N rich films (N/Si = 1.5). The peak position of the Si–H stretching mode in the FTIR spectrum is discussed using the chemical induction model. It is shown that especially for Si-rich films the hydrogen content affects the Si–H peak position. The influence of the composition on the refractive index of the films is discussed on the basis of the Lorentz–Lorenz equation and the Kramers–Kronig relation. The decreasing refractive index with increasing N/Si ratio is primarily caused by an increase of the band gap.