METHOD FOR FABRICATING CAPACITOR

摘要

PURPOSE: A method for fabricating a capacitor is provided to prevent a titanium of a titanium film from being diffused into a ferroelectric film through an upper electrode of a capacitor. CONSTITUTION: In a method for fabricating a capacitor, an interlayer insulation film(14,16) is formed on a semiconductor substrate(10) which comprises a gate electrode(13) and a bit line(15). A contact hole is formed by etching the interlayer insulation film(14,16) so as to expose a junction of a transistor. A polysilicon film(17) is deposited on an entire surface of a resultant structure. A polysilicon plug is formed in the contact hole by polishing the polysilicon film until a surface of the interlayer insulation layer(14,16) is exposed. A platinum lower electrode(18), a ferroelectric film(19) and a Ta-Nb oxide film(20) are formed on an entire surface of a resultant structure. A ratio of Ta to Nb is 7:3. A rapid thermal annealing is performed at a temperature of 600 to 1100°C, and a platinum upper electrode(21) is formed on the oxide film(20).