CONDUCTION MECHANISM AND TEMPERATURE-DEPENDENT CURRENT-VOLTAGE IN (BA, SR)TIO3 THIN-FILMS

RF magnetron sputtered (Ba, Sr)TiO3 (BST) thin films were deposited on Pt/SiO substrate with various O-2/(O-2 + Ar) mixing ratios (OMR) rang ing from 0 to 60%. Two possible conduction mechanisms of the BST thin films, the Poole-Frenkel (PF) transport (bulk limited conduction) and the Schottky emission (SE) (electrode limited conduction) were studied . Experimental results indicated that the BST films prepared at low OM R (0-25%) exhibit the SE mechanism dominated below the transition elec tric field of 490 kV/cm and the PF transport mechanism dominated beyon d 490 kV/cm; and while those prepared at high OMR (40-60%) display the SE mechanism dominated both below and beyond the transition electric field. The difference in dominant mechanism (bulk and electrode limite d conduction) between films was ascribed to concentration variation of the oxygen vacancy in the films.