Dependence of the relative sensitivity factor of nitrogen on various oxynitride dielectric matrixes

The relative sensitivity factor (RSF) plays a critical role in the quantification of nitrogen concentration in oxynitride gate oxide measured using secondary ion mass spectrometry (SIMS). The RSF depends primarily on the matrixes where the nitrogen resides under conditions in which the parametric settings of the SIMS equipment remain unchanged. In this article, different types of oxynitride dielectric films have been prepared under several different fabrication processes including decoupled plasma nitridation, thermal nitridation by nitric oxide (NO) and nitrous oxide (N2O), which resulted in the formation of significantly different chemical bonding and micro-structures for the oxynitride. The nitrogen RSF values of these oxynitride films were determined using the ratio of the species SiN− and 30Si− from the Time-of-Flight SIMS. It was found that the overall RSF values from the point-by-point algorithm ranged from 1.15 × 1021 to 2.41 × 1021 atoms/cm3. These account for about 2 times the difference in the RSF values.