DEFECT STRUCTURE IN NITROGEN-RICH AMORPHOUS-SILICON NITRIDE FILMS

Electron spin resonance and photoluminescence measurements were carrie d out on nitrogen-rich, hydrogenated amorphous silicon-nitride films. Paramagnetic Si dangling bonds (K-0 centers) are found in as-deposited films only after UV illumination. High temperature post-deposition an nealing, followed by UV illumination, creates ESR-active, two-fold coo rdinated nitrogen dangling bonds (N-2(0) centers). These two types of spin center are normally observed at room temperature. An extra compon ent appears on the ESR spectrum measured at low temperature (6 K) for the as-deposited samples after UV illumination, at which temperature t he line of the KO center is saturated by microwave power. This compone nt is tentatively attributed to N-2(0) centers that are partially satu rated. The photoluminescence efficiency is significantly decreased by the high temperature annealing. (C) 1998 Elsevier Science B.V. All rig hts reserved.