| 摘要 |
This invention provides a semiconductor memory device having a capacitor which comprises a ferroelectric layer with the perovskite crystal structure which, being expressed by the general formula ABO3, contains lead (Pb) as the element A occupying lattice A and zirconium (Zr) and titanium (Ti) as the element B occupying lattice B, and a lower electrode and an upper electrode which are disposed to sandwich said ferroelectric layer; wherein said ferroelectric layer has, both on the side of said lower electrode and on the side of said upper electrode, a region each, in which a ratio of Zr to Ti (a Zr/Ti ratio) is equal to or greater than a Zr/Ti ratio of the central section of said ferroelectric layer in the direction of thickness, and the Zr/Ti ratio of at least one of the regions on the side of said lower electrode and on the side of said upper electrode is greater than the Zr/Ti ratio of said central section.
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