High rate deposition of silicon nitride films by APCVD

Abstract

Silicon nitride films have been prepared by atmospheric pressure chemical vapor deposition (APCVD) on moving glass substrates from a gas mixture of monosilane, ammonia and nitrogen. The CVD reactor system used in this work is similar to those used in APCVD during a float glass production process (on-line CVD). At the substrate temperature of 830 °C, we prepared silicon nitride films and the deposition rate was over 10 nm/s. The deposition rates measured are not high enough at the temperatures typical of most on-line processes (650–750 °C). The deposition rate and the characteristics of silicon nitride films have been investigated using ellipsometry, X-ray photoemission spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). The obtained film is transparent and the refractive index at the wavelength of 550 nm is 1.90–1.97. The film composition depends on the ratio of NH 3 to SiH 4 in the source gas and the hydrogen concentration is approximately 15%. It seems that hydrogen atoms incorporated in the film affect properties of the films.