Patent ID: 6515322
Filing Date: 2003-02-04
Classification: H01L

Abstract:
A nonvolatile ferroelectric semiconductor memory comprising:a semiconductor substrate; a gate electrode formed on a gate insulator film on a principal surface of the semiconductor substrate; a pair of source/drain regions formed in a principal surface region of the semiconductor substrate so as to locate the gate electrode between the pair of source/drain regions; and the gate insulator film including a first insulating film in contact with the principal surface of the semiconductor substrate, and a second insulating film in contact with the first insulating film, the second insulating film being formed of a ferroelectric oxide having a dielectric constant of not larger than 50, wherein the second insulating film has a thickness which is substantially greater than the thickness of the first insulating film, and wherein the ferroelectric semiconductor memory positively utilizes an inversion of a spontaneous polarization of the ferroelectric oxide for storage, wherein the first insulating film is formed of a film selected from the group consisting of a silicon oxynitride film and a laminated layer composed of an underlying silicon oxide film in contact with the principal surface of the semiconductor substrate and an overlying silicon nitride film in contact with the second insulating film formed of the ferroelectric oxide.