Samsung Electronics Co., Ltd.

Wan-in Lee

Jun-ki Lee

Seshu B Desu

In-kyung Yoo

Chi-won Chung

Il-sub Chung

This invention is related to the manufacturing method of ferroelectric capacitor, which can be applied to the memory cell of FRAM (Ferroelectric Random Access Memory). Fabrication of ferroelectric capacitor comprising the steps of: coating a first PZT sol-gel solution on a RuO.sub.X electrode to form a first PZT layer; baking the first PZT layer; annealing the first PZT layer to produce a seed layer with a perovskite structure; coating a second PZT sol-gel solution on the seed layer to form a second PZT layer; baking the second PZT layer; and annealing the second PZT layer to form a PZT film with a perovskite structure. The ferroelectric capacitor not only has a lower leakage current level and a higher degree of remanent polarization than the conventional capacitor, but also has almost the same leakage current level as an existing Pt/PZT/Pt capacitor.

Method for manufacturing ferroelectric capacitor

An organometallic lead precursor, represented by following formula:

Organometallic lead precursor, in-situ synthesis thereof, lead-titanium

An organometallic zirconium precursor, represented by following formula:

Organometallic zirconium precursor, in-situ synthesis thereof,

Preparation method for lead-zirconium-titanium based thin film

Preparation method for lead-titanium based thin film

PZT ferroelectric thin films for capacitors comprise a combination of a donor dopant and an acceptor dopant in a total amount of about 0.1 to 8 mole percent of PZT, or Sc alone in an amount of about 0.1 to 5 mole percent. Nb or Ta is employed as a donor dopant, while Sc, Mg or Zn can be used as an acceptor dopant. The presence of a single Sc acceptor dopant, or both an acceptor dopant and a donor dopant, results in increased endurance. Fatigue cycles are increased on the order of about 10.sup.5 relative to dopant-free films. Doping with a single Sc acceptor dopant, or both an acceptor dopant and a donor dopant, reduces coercive field, allowing PZT films to switch at relatively low voltages. PZT thin films of a pure perovskite phase are obtained in which a pyrochlore phase is completely excluded. Pt may be used as an electrode material. The leakage current of PZT films doped with both the acceptor and donor elements are similar to the leakage current level of pure PZT thin films.

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Kyungki-do, South Korea

Wan-in Lee