Improvement of leakage currents of Pt/(Ba, Sr)TiO3/Pt capacitors

Pt/(Ba, Sr)TiO3/Pt capacitors fabricated by sputtering technique showed abnormally higher leakage current when negative bias was applied to the top electrode. In this letter, two kinds of processes were attempted to reduce high leakage current of Pt/BST/Pt capacitors for dynamic random access memory devices: (1) postannealing under O-2 atmosphere and (2) adding oxygen into sputtering gas of platinum top electrode. These 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 processes, so that we could obtain symmetric current versus voltage curves of Pt/BST/Pt capacitors. (C) 1997 American Institute of Physics.