TIME-DEPENDENT LEAKAGE CURRENT BEHAVIOR OF INTEGRATED BA0-7SR0.3TIO3 THIN-FILM CAPACITORS DURING STRESSING

Time-dependent leakage current behavior of integrated Ba0.7Sr0.3TiO3 c apacitors accelerated by stresses in excess of operating temperature a nd voltage was studied. Current-voltage (J-V) studies revealed that th e 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 temp eratures is of the Frenkel-Poole emission type, the leakage current in creases rapidly with time. The difference in the initial leakage curre nts is related to the difference in him growth conditions which determ ine the formation of defects in the films. The time-dependent increase in leakage current is ascribed to a change in the conduction mechanis m from the interface-controlled Schottky type to the bulk-related spac e-charge-limited type due to the accumulation of oxygen vacancies near the cathode as a result of interface barrier lowering and the migrati on of distributed oxygen vacancies across the film.