Time-Dependent Leakage Current Behavior of Integrated Ba0.7Sr0.3TiO3 Thin Film Capacitors during Stressing

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Abstract
Time-dependent leakage current behavior of integrated Ba0.7Sr0.3TiO3 capacitors accelerated by stresses in excess of operating temperature and voltage was studied. Current-voltage (J-V) studies revealed that the time-dependent leakage current behaviors are different according to the initial conduction process. When the initial leakage current of a fully processed integrated capacitor at high voltages at elevated temperatures is of the Frenkel-Poole emission type, the leakage current increases rapidly with time. The difference in the initial leakage currents is related to the difference in film growth conditions which determine the formation of defects in the films. The time-dependent increase in leakage current is ascribed to a change in the conduction mechanism from the interface-controlled Schottky type to the bulk-related space-charge-limited type due to the accumulation of oxygen vacancies near the cathode as a result of interface barrier lowering and the migration of distributed oxygen vacancies across the film.