Heat‐proof properties of Ta2N anodized thin‐film capacitors prepared at low anodization voltage

To clarify how the high heat-proof properties of Ta2N anodized film capacitors are maintained when the film thickness is reduced, the effects of heat treatment temperature increase on dissipation factor (tan δ), temperature coefficient of capacitance and dc leakage current are studied for a capacitor formed by reducing the anodization voltage. The results will follow. Even for the anodized capacitor prepared at a reduced anodization voltage of 80 V, there is no thermal degradation in tan δ and temperature coefficient of capacitance for the heat treatment below 400°C. The leakage current also shows a qualitatively similar behavior for a reduced anodization voltage with no change in the electrical conduction mechanism, even when the anodization voltage is reduced. On the other hand, while the leakage current of this Ta2N anodized film formed at 80 V changes little up to a heat-treatment temperature of 300°C, it increases rapidly at 350°C. However, compared to a Ta anodized film formed at 160 V anodization voltage with the same capacitance, this Ta2N anodized film formed at 80 V has a drastically improved heat resistance in terms of tan δ, temperature coefficient of capacitance and leakage current. From these results, it has been clarified that the use of Ta2N compound is an extremely effective way to maintain heat resistance while reducing the film thickness.