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

Abstract

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.