Semiconductor memory device including a capacitor an upper electrode of which being resistant of exfoliation

Abstract

On a silicon substrate 201, there are formed a silicon oxide 202, an adhesion layer 203 consisting of TiO2, a lower electrode 204 consisting of Pt, a ferroelectric thin film 205, and an upper electrode 206 consisting of Pt. A portion of the ferroelectric thin film adjacent to the upper electrode 206 is formed from a compound with a composition formula of SrBi2 (TaxNb1-x)2O9 where x=0.7. A compound with a value x in the composition formula being greater than 0.7 is used for the portion of the ferroelectric thin film adjacent to the upper electrode 206, so as to generate an appropriate number of grain boundaries on the surface of the ferroelectric film 205, the grain boundaries enabling implementation of anchoring effect between the ferroelectric film 205 and the upper electrode 206, thereby achieving prevention of exfoliation of the upper electrode 206 from the ferroelectric film 205. Therefore, the semiconductor memory device is free from exfoliation of the upper electrode film from the dielectric film and has a good yield.

Dependencies are inferred from the claim text.