Improving electrical characteristics of Ta/Ta2O5/Ta capacitors using low-temperature inductively coupled N2O plasma annealing

The electrical characteristics of Ta/Ta 2 O 5 /Ta capacitors are improved by treatments with inductively coupled N 2 O plasma. A low-temperature (250°C) and short (5 min) process was used to reduce the leakage current and improve the reliability. A low leakage current density (4.0 X 10 -10 A/cm 2 under 1 MV/cm), high breakdown field (4.2 MV/cm at 10 -6 A/cm 2 ), and lifetime of over 10 years at 1.61 MV/cm is obtained for the Ta/Ta 2 O 5 /Ta capacitor with the inductively coupled N 2 O plasma treatment. The conduction mechanism of the leakage current in the Ta/Ta 2 O 5 /Ta capacitor is discussed using current-voltage analyses and shows that the leakage current of the Ta/Ta 2 O 5 /Ta capacitor is dominated by Schottky emission. N 2 O plasma treatment can effectively reduce oxygen vacancies and the surface roughness of the Ta 2 O 5 film, inhibiting the conduction of the leakage current.

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