The structure of defects in H-doped SiNx films was investigated by using electron-spin resonance methods. It was found that a relaxation process occurred, at annealing temperatures below 600C, in compositions where the N/Si ratio was above the percolation threshold of Si-Si bonds in the nitride lattice. This was seen as an appreciable decrease in the density of paramagnetic Si dangling-bond defects; as detected by electron spin resonance. This process was attributed to a thermally activated charge transfer between metastable defects. No such relaxation occurred in films with a composition below the percolation threshold. This was suggested to be due to a positive correlation energy and a lack of structural flexibility. At higher annealing temperatures, an increase in the defect density was associated with the thermal release of H.

Defect Structure of SiNx:H Films and its Evolution with Annealing Temperature. F.L.Martínez, A. Del Prado, I.Mártil, D.Bravo, F.J.López: Journal of Applied Physics, 2000, 88[4], 2149-51