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

Abstract

The electrical characteristics of Ta/Ta2O5/Ta capacitors are improved by treatments with inductively coupled N2O plasma. A low-temperature (250 degrees C) and short (5 min) process was used to reduce the leakage current and improve the reliability. A low leakage current density (4.0x10(-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/Ta2O5/Ta capacitor with the inductively coupled N2O plasma treatment. The conduction mechanism of the leakage current in the Ta/Ta2O5/Ta capacitor is discussed using current-voltage analyses and shows that the leakage current of the Ta/Ta2O5/Ta capacitor is dominated by Schottky emission. N2O plasma treatment can effectively reduce oxygen vacancies and the surface roughness of the Ta2O5 film, inhibiting the conduction of the leakage current. (c) 2007 The Electrochemical Study.