Properties of anodic oxide films prepared on nitrogen-doped tantalum films

Capacitors prepared from thin films of tantalum nitride, which has an h.c.p. structure, show various excellent electrical properties. TaN capacitors, in particular, exhibit great endurance to heat treatment and have no polarity in their anodic and cathodic leakage currents. The structure of these anodic films, their dielectric properties and their electrical conduction characteristics were studied. An anodic film formed on a nitrogen-doped tantalum film was shown to consist of two layers by analysis using the chemical etching method and by Auger electron spectroscopy. The first layer, which is situated at the oxide-electrolyte interface, has a high density and includes very little nitrogen. The second layer is porous and contains excess nitrogen.