Patent ID: 6841817

Claim:
A ferroelectric capacitor comprising: a lower electrode; a ferroelectric film provided over said lower electrode and having a perovskite-type structure; and an upper electrode provided over said ferroelectric film, wherein said ferroelectric film includes a first ferroelectric film part having a first crystal system and formed along an interface with said lower electrode, a second ferroelectric film part having a second crystal system and being formed on the first ferroelectric film part, and a third ferroelectric film part having said first crystal system and being formed between said second ferroelectric film part and an interface with said upper electrode, wherein said first crystal system is selected from a group consisting of a rhombohedral system and an orthorhombic system, and said second crystal system is a tetragonal system, and wherein said first crystal system reduces a shift of a coercive voltage caused by an accumulation of electric charges at the interfaces with the electrodes.