EPR spectra of amorphous silicon nitride films grown by low-temperature PECVD

Electron paramagnetic resonance (EPR) study of silicon nitride films prepared at 120 °C by plasma enhanced chemical vapor deposition (PECVD) is reported. The complex EPR line with contribution from surface defects and hyperfine structure (HFS) is observed in N-rich samples. The HFS spectrum with peak-to-peak separation ∼8 G cannot be attributed to known defect models. However, it is well described by spin-Hamiltonian of unpaired electron interacting with three equivalent nuclei having nuclear spin of 1. The structural identification of the defect responsible for the HFS is discussed.