ELECTRON-PARAMAGNETIC-RESONANCE INVESTIGATION OF CHARGE TRAPPING CENTERS IN AMORPHOUS-SILICON NITRIDE FILMS

We have explored the nature of the silicon dangling-bond center in amo rphous hydrogenated silicon nitride (a-SiN(x):H) thin films, and its r elationship to the charge trapping centers using electron paramagnetic resonance (EPR) and capacitance-voltage (C-V) measurements. We have i nvestigated the quantitative relationship between the concentration of silicon dangling bonds using EPR and the concentration of charge trap s, measured by C-V measurements, for both UV-illuminated and unillumin ated a-SiN(x):H thin films subjected to both electron and hole injecti on sequences. A theoretical framework for our results is also discusse d. These results continue to support a model in which the Si dangling bond is a negative-U defect in silicon nitride, and that a change in c harge state of preexisting positively and negatively charged Si sites is responsible for the trapping phenomena observed in these thin film dielectrics.