FTIR characterization of light emitting Si-rich nitride films prepared by low pressure chemical vapor deposition

We report on the infrared transmission and light emission of Si-rich nitride (SRN) films prepared by low pressure chemical vapor deposition (LPCVD) from dichlorosilane (SiH2Cl2, DCS) and ammonia (NH3) mixtures. The main absorption band at about 830 cm− 1, attributed to Si–N vibration mode and observed in stoichiometric silicon nitride, shifted to slightly higher wavenumbers with increasing Si content in the SRN films. Annealing at temperatures higher than the deposition temperature induced a further shift of the main band to higher wavenumbers. Additionally, a new band appeared as a “shoulder” at about 1080 cm− 1, attributed to partial oxidation of the silicon nanocrystals. Photoluminescence (PL) obtained from the SRN films increased considerably and shifted to shorter wavelengths as the Si content decreased whereas annealing caused further enhancement and a slight shift to shorter wavelengths in comparison with the as-grown films.