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US 6,617,626 B2Granted
Ferroelectric semiconductor memory device and a fabrication process thereof
AssigneeFujitsu Limited
InventorsSoichiro Ozawa, Shan Sun, Hideyuki Noshiro, George Hickert, Katsuyoshi Matsuura, Fan Chu, Takeyasu Saito
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Abstract
A ferroelectric random access memory has a ferroelectric capacitor formed of a stacking of a lower electrode, a PZT film and an upper electrode of SrRuO3, wherein the PZT film includes pinholes, with a pinhole density of about 17/μm2 or less.
Claims6
A ferroelectric random access memory, comprising:
- a substrate carrying thereon an active device;
- a lower electrode provided over said substrate in electrical connection with said active layer;
- a ferroelectric film containing at least Pb, Zr and Ti and having a perovskite structure, said ferroelectric film comprising a number of crystal grains extending continuously from a bottom surface to a top surface of said ferroelectric film and forming a columnar microstructure, said crystal grains having pinholes;
- and
- an upper electrode of a conductive oxide film provided on said ferroelectric film, said upper electrode having a perovskite structure and containing therein Sr and Ru,
- said ferroelectric film further containing Ca and Sr,
- said ferroelectric film including said pinholes with a density not exceeding 34 pinholes/μm2.
4 more elements
Dependencies are inferred from the claim text.