Effect of growth parameters on refractive index and film composition of plasma enhanced chemical vapor deposition silicon oxynitride films

The importance of silicon oxynitride (SiOxNy) for optoelectronic device applications is ever increasing owing to its tunable refractive index. In this research, the influence of deposition conditions on film properties, correlated with film composition and bonding, have been investigated. Thick SiOxNy films were deposited in a plasma enehanced chemical vapor deposition reactor using silane (SiH4) and nitrous oxide (N2O) as precursor gases. To investigate the influence of deposition conditions on film properties, three different parameters were studied; gas flow ratio, RF plasma mixed frequency ratio and RF power. Several different SiOxNy films were deposited at varying conditions. The temperature and pressure were maintained at 350 degrees C and I Torr during all the experimental runs. The films were characterized for refractive index, growth rate and residual stress. The refractive index and he thickness of the films were measured using a prism-coupling technique. For composition analysis, x-ray photoelectron spectroscopy studies and elastic recoil detection analysis were undertaken. The materials analysis was used to determine the correlation between growth parameters and material chemistry. In addition, the correlation between material chemistry and refractive index was also investigated.