Intrinsic Stress of Pecvd Silicon Oxynitride Films Deposited in a Hot-Wall Reactor

Abstract

Plasma enhanced chemical vapor deposited ( PECVD ) silicon oxynitride films with refractive indices varying from 1.65 to 1.85 have been deposited in a hot-wall reactor using a SiH4/NH3/N2O gas mixture. A systematic investigation of the variation of the intrinsic stress of the deposited films with the parameters of deposition and the properties of the films, has been carried out. Our results show that silicon oxynitride films deposited in optimal conditions can support annealing temperatures of 900°C without cracking. The mechanical stresses in the films were determined by the Newton's fringes technique and a surface profiler. The film thickness was measured by ellipsometry at a wavelength of 632.8 nm. Fourier transform infrared spectroscopy ( FTIR ) was used to measure the hydrogen content of the films. The composition of the silicon oxynitride films was determined by Auger electron spectroscopy ( AES ) and Rutherford backscattering spectrometry ( RBS ).