Rapid thermal annealing effects on the structural properties and density of defects in $SiO2$ and $SiNx:H$ films deposited by electron cyclotron resonance

The effect of rapid thermal annealing processes on the properties of $SiO2.0$ and $SiN1.55$ films was studied. The films were deposited at room temperature from $N2$ and $SiH4$ gas mixtures, and $N2,$ $O2,$ and $SiH4$ gas mixtures, respectively, using the electron cyclotron resonance technique. The films were characterized by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance spectroscopy. According to the FTIR characterization, the $SiO2.0$ films show continuous stress relaxation for annealing temperatures between 600 and 1000 °C. The properties of the films annealed at 900–1000 °C are comparable to those of thermally grown ones. The density of defects shows a minimum value for annealing temperatures around 300–400 °C, which is tentatively attributed to the passivation of the well-known $E′$ center Si dangling bonds due to the formation of Si–H bonds. A very low density of defects $(5×1016 cm−3)$ is observed over the whole annealing temperature range. For the $SiN1.55$ films, the highest structural order is achieved for annealing temperatures of 900 °C. For higher temperatures, there is a significant release of H from N–H bonds without any subsequent Si–N bond healing, which results in degradation of the structural properties of the film. A minimum in the density of defects is observed for annealing temperatures of 600 °C. The behavior of the density of defects is governed by the presence of non-bonded H and Si–H bonds below the IR detection limit.