Studies of optical properties of silicon-rich silicon nitride thin films

Abstract

Silicon-rich silicon nitride (SRN) thin films were synthesized by either Si ion implantation into silicon nitride films or plasma enhanced chemical vapor deposition (PECVD). Si nanoparticles embedded in the silicon nitride matrix are precipitated by the excess Si atoms. Optical properties of the Si nanoparticles embedded in the silicon nitride matrix have been investigated with spectroscopic ellipsometry. Strong light emissions from different SRN films under optical pumping (i.e., photoluminescence or PL) or electrical pumping (i.e., electroluminescence or EL) have been observed. The PL properties and mechanisms have been studied. Strong visible EL with electrically-tunable colors and even white color from the light-emitting structures based on the SRN films has been demonstrated. The EL properties and their dependence on the synthesis conditions of the SNR films have been investigated. In addition, it is found that the charge trapping in SRN films strongly influences the EL properties.