Patent ID: 6855973

Claim:
A semiconductor memory device comprising: a capacitor including a lower electrode film, a dielectric film, and an upper electrode film disposed in sequence from a substrate side, wherein a portion of the dielectric film adjacent to the upper electrode film is different in composition from the other portions of the dielectric film, and wherein the portion of the dielectric film adjacent to the upper electrode film comprises SrBi 2 (Ta x Nb 1-x ) 2 O 9 , includes Nb in an amount where x is at least 0.7, and is at least 5 nm thick in order to improve adhesion of the upper electrode to the dielectric film, and wherein an amount of Nb is different in different parts of the dielectric film, so that the amount of Nb in the dielectric film is greater at a location further from the upper electrode film than at a location in the dielectric film closer to and adjacent to the upper electrode film.