IMPROVEMENT OF LEAKAGE CURRENTS OF PT (BA, SR)TIO3/PT CAPACITORS/

Pt/(Ba, Sr)TiO3/Pt capacitors fabricated by sputtering technique showe d abnormally higher leakage current when negative bias was applied to the top electrode. In this letter, two kinds of processes were attempt ed to reduce high leakage current of Pt/BST/Pt capacitors for dynamic random access memory devices: (1) postannealing under O-2 atmosphere a nd (2) adding oxygen into sputtering gas of platinum top electrode. Th ese processes were very effective to reduce the oxygen vacancy in the BST films which are mostly responsible for such a high leakage current . The higher reverse currents were significantly lowered by these proc esses, so that we could obtain symmetric current versus voltage curves of Pt/BST/Pt capacitors. (C) 1997 American Institute of Physics.