| abstract |
(57) [Abstract] [Purpose] To make it possible to use a material that is easily oxidized but that can be finely processed as the lower electrode. In addition, the interface state between the lower electrode and the insulating film is improved. [Structure] An insulating film 2 such as a silicon oxynitride film that prevents diffusion of metal from a ferroelectric film is formed on a lower electrode 1. A ferroelectric film 4 such as SrBi 2 Ta 2 O 9 is formed thereon. Since the ferroelectric film 4 is deposited after the insulating film 2 is provided in advance, the lower electrode 1 can be prevented from being oxidized. Next, the upper electrode layer 5 is formed. As a result, the state of the interface between the lower electrode 1 and the insulating film 2 is improved, the leak current is reduced, and the insulating film thickness can be controlled. Also, polysilicon, titanium, tungsten, etc., which are easily oxidized by the lower electrode material but can be finely processed, can be used. |