Low pressure chemical vapour deposition (LPCVD) silicon oxynitride films of
various compositions (from pure SiO2 to pure Si3N4) were deposited by chan
ging the relative gas Bow ratio. The effects of oxygen on the physical prop
erties of the films were studied by spectroellipsometry (using Bruggeman ap
proximation and Wemple Di Domenico model) acid infrared spectroscopy. Refra
ctive index measured by spectroellipsometry method is studied as a function
of some deposition parameters: temperature of deposition, gases fluxes rat
io. The high value of deposition temperature means low values in refractive
index. More oxygen into films decreases the refractive index, The refracti
ve index dispersion is studied by single-oscillator Wemple Di Domenico mode
l. The optical band gap varies monotonically from 5 eV for silicon nitride,
to 9eV for HTO LPCVD silicon dioxide and for the studied silicon oxynitrid
e was found to be between 5 and 6 eV. (C) 1999 Elsevier Science S.A. AU rig
hts reserved.