The bulk properties of SiNx:H thin film dielectrics and interface characteristics of SiNx:H/Si devices were studied by a combination of electrical measurements (capacitance–voltage and current–voltage characteristics) and defect spectroscopy (electron spin resonance). The SiNx:H films were deposited by an electron cyclotron resonance plasma method and subjected to rapid thermal annealing post-deposition treatments at between 300 and 1050C for 30s. It was found that the response of the dielectric to the thermal treatments was strongly affected by its N to Si ratio (N/Si = x) being above or below the percolation threshold of the Si–Si bonds in the SiNx:H lattice, and by the amount and distribution of the H content. The density of Si dangling bond defects decreases at moderate annealing temperatures (below 600C) in one order of magnitude for the compositions above the percolation threshold (N rich, x = 1.55, and near stoichiometric, x = 1.43). For the N rich films, a good correlation existed between the Si dangling bond density and the interface trap density, obtained from the capacitance measurements. This suggested that the observed behavior was mainly determined by the

removal of states from the band tails associated to Si–Si weak bonds, because of the thermal relaxation of the bonding strain. At higher annealing temperatures the deterioration of the electrical properties and the increase of the Si dangling bonds seem to be associated with a release of trapped H from micro-voids of the structure. For the Si rich samples rigidity percolates in the network resulting in a rigid and strained structure for which the degradation phenomena starts at lower temperatures than for the other two types of samples.

Temperature Effects on the Electrical Properties and Structure of Interfacial and Bulk Defects in Al/SiNx:H/Si Devices. F.L.Martínez, E.San Andrés, A.del Prado, I.Mártil, D.Bravo, F.J.López: Journal of Applied Physics, 2001, 90[3], 1573-8