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US 6,440,754 B2Granted
Thin film ferroelectric capacitors having improved memory retention through the use of essentially smooth bottom electrode structures
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsShinichiro Hayashi, Tatsuo Otsuki
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Abstract
A ferroelectric thin film capacitor has smooth electrodes permitting comparatively stronger polarization, less fatigue, and less imprint, as the ferroelectric capacitor ages. The smooth electrode surfaces are produced by carefully controlled drying, soft baking, and annealing conditions.
Claims7
A method of making a ferroelectric capacitor, said method comprising the steps of:
- forming an essentially smooth bottom electrode;
- depositing a liquid precursor on said bottom electrode to provide a precursor film, said precursor film being capable of yielding a ferroelectric layered superlattice material upon drying and annealing of said precursor film;
- drying said precursor film at a temperature less than 400° C. to provide a dried precursor residue;
- soft baking said dried precursor residue using RTP at an RTP temperature ranging from 625° C. to 725° C. for a period of time ranging from thirty seconds to five minutes to provide a soft baked precursor residue;
- and
- annealing said soft baked precursor residue.
3 more elements
Dependencies are inferred from the claim text.